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SMD code search: identify a part by its marking

26 printed with a similar-looking code.

Not sure which one you have?

Answer up to 4 quick questions and these 26 parts are ranked, with a meter test that settles it. It works on a dead part too.

Nothing is printed exactly Z51

These parts are printed with a character that is easy to misread as what you typed. The odd one out is marked on each.

  • SGM41030-27D43GN6Gprinted 2S1SOT-23-6Battery protection IC, 6 pins, SG MicroBattery protection IC6 pinsSG Micro

    Printed 2S1 on the part. Easy to misread as Z51. Check that character with a loupe before you order anything.

    What it is
    Battery protection IC
    Maker
    SG Micro
    Package
    SOT-23-6
    Pins
    6
    Details
    Over-Voltage Protection for 2-Series to 3-Series Li-lon Batteries with Low Operating Consumption
    Source
    Manufacturer datasheet

    Is it dead?

    Voltage with the board powered; ohms from each pin to ground with it off.

    Working, it reads

    Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.

    Dead, it reads

    • A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
    • Supply present, output stuck: failed, or its load has.
    On the board:
    A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
    Compare:
    The surest reference is the same IC on a working board, measured pin by pin.
    Watch for:
    Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

    Datasheetfor SGM41030-27D43GN6G, opens in a new tab
  • LN5121B0055Mprinted ZS1SOT-23-6DC-DC converter, 6 pins, Shanghai Natlinear ElectronicsDC-DC converter6 pinsShanghai Natlinear Electronics

    Printed ZS1 on the part. Easy to misread as Z51. Check that character with a loupe before you order anything.

    What it is
    DC-DC converter
    Maker
    Shanghai Natlinear Electronics
    Package
    SOT-23-6
    Pins
    6
    Details
    DC/DC voltage converter IC: PWM st-up, Vfb=0.055V, 300mA, 1MHz, +CE
    Source
    Published code list

    Is it dead?

    Voltage with the board powered; ohms from each pin to ground with it off.

    Working, it reads

    Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.

    Dead, it reads

    • A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
    • Supply present, output stuck: failed, or its load has.
    On the board:
    A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
    Compare:
    The surest reference is the same IC on a working board, measured pin by pin.
    Watch for:
    Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • LN5121B0140Mprinted ZSLSOT-23-6DC-DC converter, 6 pins, Shanghai Natlinear ElectronicsDC-DC converter6 pinsShanghai Natlinear Electronics

    Printed ZSL on the part. Easy to misread as Z51. Check that character with a loupe before you order anything.

    What it is
    DC-DC converter
    Maker
    Shanghai Natlinear Electronics
    Package
    SOT-23-6
    Pins
    6
    Details
    DC/DC voltage converter IC: PWM st-up, Vfb=0.140V, 300mA, 1MHz, +CE
    Source
    Published code list

    Is it dead?

    Voltage with the board powered; ohms from each pin to ground with it off.

    Working, it reads

    Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.

    Dead, it reads

    • A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
    • Supply present, output stuck: failed, or its load has.
    On the board:
    A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
    Compare:
    The surest reference is the same IC on a working board, measured pin by pin.
    Watch for:
    Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • XC6420AB51MR-Gprinted 251SOT-23-6LDO regulator, 6 pins, TorexLDO regulator6 pinsTorex

    Printed 251 on the part. Easy to misread as Z51. Check that character with a loupe before you order anything.

    What it is
    LDO regulator
    Maker
    Torex
    Package
    SOT-23-6
    Pins
    6
    Details
    Linear voltage regulator IC: LDO, Dual out, Vout1/Vout2=3.10/3.10V±2%, 150mA, +CE
    Source
    Published code list

    Is it dead?

    Voltage, board powered, black probe on ground. Then ohms with the power off.

    Working, it reads

    Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

    Dead, it reads

    • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
    • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
    • Power off, input to output near 0 Ω: shorted.
    On the board:
    An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
    Compare:
    The same regulator on another rail or another board shows the right voltages and the right resistances.
    Watch for:
    Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • XZ5121B005Mprinted ZS1SOT-23-6LED driver, 6 pinsLED driver6 pinsNot recorded

    Printed ZS1 on the part. Easy to misread as Z51. Check that character with a loupe before you order anything.

    What it is
    LED driver
    Maker
    Not recorded
    Package
    SOT-23-6
    Pins
    6
    Source
    Published code list

    Is it dead?

    Voltage with the board powered; ohms from each pin to ground with it off.

    Working, it reads

    Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.

    Dead, it reads

    • A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
    • Supply present, output stuck: failed, or its load has.
    On the board:
    A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
    Compare:
    The surest reference is the same IC on a working board, measured pin by pin.
    Watch for:
    Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • XZ5121B014Mprinted ZSLSOT-23-6LED driver, 6 pinsLED driver6 pinsNot recorded

    Printed ZSL on the part. Easy to misread as Z51. Check that character with a loupe before you order anything.

    What it is
    LED driver
    Maker
    Not recorded
    Package
    SOT-23-6
    Pins
    6
    Source
    Published code list

    Is it dead?

    Voltage with the board powered; ohms from each pin to ground with it off.

    Working, it reads

    Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.

    Dead, it reads

    • A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
    • Supply present, output stuck: failed, or its load has.
    On the board:
    A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
    Compare:
    The surest reference is the same IC on a working board, measured pin by pin.
    Watch for:
    Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

  • 20 more parts have no package on record. Nothing rules them out, so they stay.
    • FDMA86251printed 251N-channel MOSFET, onsemiN-channel MOSFETNot recordedonsemi

      Printed 251 on the part. Easy to misread as Z51. Check that character with a loupe before you order anything.

      What it is
      N-channel MOSFET
      Maker
      onsemi
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Single N-Channel PowerTrench MOSFET
      Source
      Manufacturer datasheet

      Is it dead?

      Diode range, part lifted. Test drain to source first, then short gate to source and test again.

      Working, it reads

      Red probe on the source, black on the drain: about 0.4 to 0.9 V, the body diode. Open the other way. The gate reads open to both other pins, both ways.

      Dead, it reads

      • Drain to source the same both ways, near 0 V with a continuous beep, and still so after shorting gate to source: shorted. The classic failure.
      • The gate reads low to source or drain: gate shorted. Often all three pins end up shorted together.
      • No body diode at all: failed open.
      On the board
      the gate usually has a resistor to the source, so gate to source reads that resistor, which is not a fault. A drain short can be the load. Lift a leg to be sure.
      Compare:
      If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.
      Watch for:
      The diode range can charge the gate enough to turn the part on, and then drain to source reads near 0 both ways on a good part. Short gate to source and test again before you condemn it.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

      Datasheetfor FDMA86251, opens in a new tab
    • LN2312SLT1Gprinted 2SLN-channel MOSFET, LRCN-channel MOSFETNot recordedLRC

      Printed 2SL on the part. Easy to misread as Z51. Check that character with a loupe before you order anything.

      What it is
      N-channel MOSFET
      Maker
      LRC
      Package
      Not recorded
      Pins
      Not recorded
      Details
      MOSFET, N-Channel, VDSS 20 V, VGS 12 V
      Source
      Manufacturer datasheet

      Is it dead?

      Diode range, part lifted. Test drain to source first, then short gate to source and test again.

      Working, it reads

      Red probe on the source, black on the drain: about 0.4 to 0.9 V, the body diode. Open the other way. The gate reads open to both other pins, both ways.

      Dead, it reads

      • Drain to source the same both ways, near 0 V with a continuous beep, and still so after shorting gate to source: shorted. The classic failure.
      • The gate reads low to source or drain: gate shorted. Often all three pins end up shorted together.
      • No body diode at all: failed open.
      On the board
      the gate usually has a resistor to the source, so gate to source reads that resistor, which is not a fault. A drain short can be the load. Lift a leg to be sure.
      Compare:
      If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.
      Watch for:
      The diode range can charge the gate enough to turn the part on, and then drain to source reads near 0 both ways on a good part. Short gate to source and test again before you condemn it.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

      Datasheetfor LN2312SLT1G, opens in a new tab
    • S-1335A33-A4T2U3printed 251LDO regulator, ABLICLDO regulatorNot recordedABLIC

      Printed 251 on the part. Easy to misread as Z51. Check that character with a loupe before you order anything.

      What it is
      LDO regulator
      Maker
      ABLIC
      Package
      Not recorded
      Pins
      Not recorded
      Details
      5.5 V INPUT, 150 mA VOLTAGE REGULATOR WITH SOFT-START FUNCTION
      Source
      Manufacturer datasheet

      Is it dead?

      Voltage, board powered, black probe on ground. Then ohms with the power off.

      Working, it reads

      Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

      Dead, it reads

      • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
      • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
      • Power off, input to output near 0 Ω: shorted.
      On the board:
      An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
      Compare:
      The same regulator on another rail or another board shows the right voltages and the right resistances.
      Watch for:
      Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

      Datasheetfor S-1335A33-A4T2U3, opens in a new tab
    • AP6213A-12DHNGSprinted 25LLDO regulator, Anwell SemiconductorLDO regulatorNot recordedAnwell Semiconductor

      Printed 25L on the part. Easy to misread as Z51. Check that character with a loupe before you order anything.

      What it is
      LDO regulator
      Maker
      Anwell Semiconductor
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Linear voltage regulator IC: LDO, 1.2V±2%, 300mA, +CE, PDR, H-free
      Source
      Published code list

      Is it dead?

      Voltage, board powered, black probe on ground. Then ohms with the power off.

      Working, it reads

      Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

      Dead, it reads

      • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
      • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
      • Power off, input to output near 0 Ω: shorted.
      On the board:
      An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
      Compare:
      The same regulator on another rail or another board shows the right voltages and the right resistances.
      Watch for:
      Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

    • AP6213A-12DHNGS1printed 25LLDO regulator, Anwell SemiconductorLDO regulatorNot recordedAnwell Semiconductor

      Printed 25L on the part. Easy to misread as Z51. Check that character with a loupe before you order anything.

      What it is
      LDO regulator
      Maker
      Anwell Semiconductor
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Linear voltage regulator IC: LDO, 1.2V±1%, 300mA, +CE, PDR, H-free
      Source
      Published code list

      Is it dead?

      Voltage, board powered, black probe on ground. Then ohms with the power off.

      Working, it reads

      Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

      Dead, it reads

      • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
      • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
      • Power off, input to output near 0 Ω: shorted.
      On the board:
      An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
      Compare:
      The same regulator on another rail or another board shows the right voltages and the right resistances.
      Watch for:
      Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

    • AP6213A-12DHNGUprinted 25LLDO regulator, Anwell SemiconductorLDO regulatorNot recordedAnwell Semiconductor

      Printed 25L on the part. Easy to misread as Z51. Check that character with a loupe before you order anything.

      What it is
      LDO regulator
      Maker
      Anwell Semiconductor
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Linear voltage regulator IC: LDO, 1.2V±2%, 300mA. +CE, PDR, H-free
      Source
      Published code list

      Is it dead?

      Voltage, board powered, black probe on ground. Then ohms with the power off.

      Working, it reads

      Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

      Dead, it reads

      • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
      • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
      • Power off, input to output near 0 Ω: shorted.
      On the board:
      An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
      Compare:
      The same regulator on another rail or another board shows the right voltages and the right resistances.
      Watch for:
      Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

    • AP6213A-12DHNGU1printed 25LLDO regulator, Anwell SemiconductorLDO regulatorNot recordedAnwell Semiconductor

      Printed 25L on the part. Easy to misread as Z51. Check that character with a loupe before you order anything.

      What it is
      LDO regulator
      Maker
      Anwell Semiconductor
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Linear voltage regulator IC: LDO, 1.2V±1%, 300mA. +CE, PDR, H-free
      Source
      Published code list

      Is it dead?

      Voltage, board powered, black probe on ground. Then ohms with the power off.

      Working, it reads

      Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

      Dead, it reads

      • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
      • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
      • Power off, input to output near 0 Ω: shorted.
      On the board:
      An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
      Compare:
      The same regulator on another rail or another board shows the right voltages and the right resistances.
      Watch for:
      Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

    • AP6213A-12DHNGWprinted 25LLDO regulator, Anwell SemiconductorLDO regulatorNot recordedAnwell Semiconductor

      Printed 25L on the part. Easy to misread as Z51. Check that character with a loupe before you order anything.

      What it is
      LDO regulator
      Maker
      Anwell Semiconductor
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Linear voltage regulator IC: LDO, 1.2V±2%, 300mA, +CE, PDR, H-free
      Source
      Published code list

      Is it dead?

      Voltage, board powered, black probe on ground. Then ohms with the power off.

      Working, it reads

      Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

      Dead, it reads

      • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
      • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
      • Power off, input to output near 0 Ω: shorted.
      On the board:
      An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
      Compare:
      The same regulator on another rail or another board shows the right voltages and the right resistances.
      Watch for:
      Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

    • AP6213A-12DHNGW1printed 25LLDO regulator, Anwell SemiconductorLDO regulatorNot recordedAnwell Semiconductor

      Printed 25L on the part. Easy to misread as Z51. Check that character with a loupe before you order anything.

      What it is
      LDO regulator
      Maker
      Anwell Semiconductor
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Linear voltage regulator IC: LDO, 1.2V±1%, 300mA, +CE, PDR, H-free
      Source
      Published code list

      Is it dead?

      Voltage, board powered, black probe on ground. Then ohms with the power off.

      Working, it reads

      Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

      Dead, it reads

      • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
      • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
      • Power off, input to output near 0 Ω: shorted.
      On the board:
      An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
      Compare:
      The same regulator on another rail or another board shows the right voltages and the right resistances.
      Watch for:
      Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

    • AP6213A-12DHNPSprinted 25LLDO regulator, Anwell SemiconductorLDO regulatorNot recordedAnwell Semiconductor

      Printed 25L on the part. Easy to misread as Z51. Check that character with a loupe before you order anything.

      What it is
      LDO regulator
      Maker
      Anwell Semiconductor
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Linear voltage regulator IC: LDO, 1.2V±2%, 300mA, +CE, PDR
      Source
      Published code list

      Is it dead?

      Voltage, board powered, black probe on ground. Then ohms with the power off.

      Working, it reads

      Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

      Dead, it reads

      • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
      • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
      • Power off, input to output near 0 Ω: shorted.
      On the board:
      An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
      Compare:
      The same regulator on another rail or another board shows the right voltages and the right resistances.
      Watch for:
      Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

    • AP6213A-12DHNPS1printed 25LLDO regulator, Anwell SemiconductorLDO regulatorNot recordedAnwell Semiconductor

      Printed 25L on the part. Easy to misread as Z51. Check that character with a loupe before you order anything.

      What it is
      LDO regulator
      Maker
      Anwell Semiconductor
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Linear voltage regulator IC: LDO, 1.2V±1%, 300mA, +CE, PDR
      Source
      Published code list

      Is it dead?

      Voltage, board powered, black probe on ground. Then ohms with the power off.

      Working, it reads

      Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

      Dead, it reads

      • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
      • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
      • Power off, input to output near 0 Ω: shorted.
      On the board:
      An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
      Compare:
      The same regulator on another rail or another board shows the right voltages and the right resistances.
      Watch for:
      Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

    • AP6213A-12DHNPUprinted 25LLDO regulator, Anwell SemiconductorLDO regulatorNot recordedAnwell Semiconductor

      Printed 25L on the part. Easy to misread as Z51. Check that character with a loupe before you order anything.

      What it is
      LDO regulator
      Maker
      Anwell Semiconductor
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Linear voltage regulator IC: LDO, 1.2V±2%, 300mA. +CE, PDR
      Source
      Published code list

      Is it dead?

      Voltage, board powered, black probe on ground. Then ohms with the power off.

      Working, it reads

      Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

      Dead, it reads

      • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
      • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
      • Power off, input to output near 0 Ω: shorted.
      On the board:
      An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
      Compare:
      The same regulator on another rail or another board shows the right voltages and the right resistances.
      Watch for:
      Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

    • AP6213A-12DHNPU1printed 25LLDO regulator, Anwell SemiconductorLDO regulatorNot recordedAnwell Semiconductor

      Printed 25L on the part. Easy to misread as Z51. Check that character with a loupe before you order anything.

      What it is
      LDO regulator
      Maker
      Anwell Semiconductor
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Linear voltage regulator IC: LDO, 1.2V±1%, 300mA. +CE, PDR
      Source
      Published code list

      Is it dead?

      Voltage, board powered, black probe on ground. Then ohms with the power off.

      Working, it reads

      Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

      Dead, it reads

      • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
      • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
      • Power off, input to output near 0 Ω: shorted.
      On the board:
      An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
      Compare:
      The same regulator on another rail or another board shows the right voltages and the right resistances.
      Watch for:
      Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

    • AP6213A-12DHNPWprinted 25LLDO regulator, Anwell SemiconductorLDO regulatorNot recordedAnwell Semiconductor

      Printed 25L on the part. Easy to misread as Z51. Check that character with a loupe before you order anything.

      What it is
      LDO regulator
      Maker
      Anwell Semiconductor
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Linear voltage regulator IC: LDO, 1.2V±2%, 300mA, +CE, PDR
      Source
      Published code list

      Is it dead?

      Voltage, board powered, black probe on ground. Then ohms with the power off.

      Working, it reads

      Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

      Dead, it reads

      • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
      • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
      • Power off, input to output near 0 Ω: shorted.
      On the board:
      An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
      Compare:
      The same regulator on another rail or another board shows the right voltages and the right resistances.
      Watch for:
      Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

    • AP6213A-12DHNPW1printed 25LLDO regulator, Anwell SemiconductorLDO regulatorNot recordedAnwell Semiconductor

      Printed 25L on the part. Easy to misread as Z51. Check that character with a loupe before you order anything.

      What it is
      LDO regulator
      Maker
      Anwell Semiconductor
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Linear voltage regulator IC: LDO, 1.2V±1%, 300mA, +CE, PDR
      Source
      Published code list

      Is it dead?

      Voltage, board powered, black probe on ground. Then ohms with the power off.

      Working, it reads

      Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

      Dead, it reads

      • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
      • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
      • Power off, input to output near 0 Ω: shorted.
      On the board:
      An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
      Compare:
      The same regulator on another rail or another board shows the right voltages and the right resistances.
      Watch for:
      Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

    • KIC7251T5printed 251Voltage supervisor, KECVoltage supervisorNot recordedKEC

      Printed 251 on the part. Easy to misread as Z51. Check that character with a loupe before you order anything.

      What it is
      Voltage supervisor
      Maker
      KEC
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Voltage detector IC: 5.1V±1%, -Reset PPO
      Source
      Published code list

      Is it dead?

      Voltage with the board powered; ohms from each pin to ground with it off.

      Working, it reads

      Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.

      Dead, it reads

      • A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
      • Supply present, output stuck: failed, or its load has.
      On the board:
      A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
      Compare:
      The surest reference is the same IC on a working board, measured pin by pin.
      Watch for:
      Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

    • S-1335A20-A4T2U3printed 25L4 pins, ABLICNot recorded4 pinsABLIC

      Printed 25L on the part. Easy to misread as Z51. Check that character with a loupe before you order anything.

      What it is
      Not recorded
      Maker
      ABLIC
      Package
      Not recorded
      Pins
      4
      Details
      equivalent [2.0V LDO]
      Source
      Published code list

      Is it dead?

      Voltage, board powered, black probe on ground. Then ohms with the power off.

      Working, it reads

      Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

      Dead, it reads

      • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
      • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
      • Power off, input to output near 0 Ω: shorted.
      On the board:
      An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
      Compare:
      The same regulator on another rail or another board shows the right voltages and the right resistances.
      Watch for:
      Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

    • TSH251CTprinted 251Not recordedNot recordedNot recorded

      Printed 251 on the part. Easy to misread as Z51. Check that character with a loupe before you order anything.

      What it is
      Not recorded
      Maker
      Not recorded
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Hall Effect Switch
      Source
      Published code list

      Is it dead?

      Diode range and ohms range, part lifted.

      Working, it reads

      Depends on what it is. The datasheet, or an identical part, says.

      Dead, it reads

      • Between two pins, the same reading both ways, near 0 V with a continuous beep: shorted.
      • Open between every pair of pins: failed open, or a part that reads open when working.
      On the board
      this is a first look only: the meter reads every path between those pins, and a short can be a neighbour. Lift one leg before you condemn it.
      Compare:
      If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

    • TSH251CXprinted 251Not recordedNot recordedNot recorded

      Printed 251 on the part. Easy to misread as Z51. Check that character with a loupe before you order anything.

      What it is
      Not recorded
      Maker
      Not recorded
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Hall Effect Switch
      Source
      Published code list

      Is it dead?

      Diode range and ohms range, part lifted.

      Working, it reads

      Depends on what it is. The datasheet, or an identical part, says.

      Dead, it reads

      • Between two pins, the same reading both ways, near 0 V with a continuous beep: shorted.
      • Open between every pair of pins: failed open, or a part that reads open when working.
      On the board
      this is a first look only: the meter reads every path between those pins, and a short can be a neighbour. Lift one leg before you condemn it.
      Compare:
      If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

    • XCL219B313FR-Gprinted 2S1DC-DC converter, TorexDC-DC converterNot recordedTorex

      Printed 2S1 on the part. Easy to misread as Z51. Check that character with a loupe before you order anything.

      What it is
      DC-DC converter
      Maker
      Torex
      Package
      Not recorded
      Pins
      Not recorded
      Details
      DC/DC voltage converter IC: PWM st-dwn, 3.0MHz, 3.1V±2%, 1.0A, +CE
      Source
      Published code list

      Is it dead?

      Voltage with the board powered; ohms from each pin to ground with it off.

      Working, it reads

      Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.

      Dead, it reads

      • A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
      • Supply present, output stuck: failed, or its load has.
      On the board:
      A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
      Compare:
      The surest reference is the same IC on a working board, measured pin by pin.
      Watch for:
      Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

29 more parts have codes that begin with Z51: 1 in SOT-23-6, 28 with no package on record

Codes that begin with Z51

For a marking with its end worn or burnt off. Each one shows its full printed code.

  • REF35300QDBVprinted 2SLISOT-23-6Voltage reference, 6 pins, Texas InstrumentsVoltage reference6 pinsTexas Instruments

    Printed 2SLI. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

    What it is
    Voltage reference
    Maker
    Texas Instruments
    Package
    SOT-23-6
    Pins
    6
    Details
    Ultra Low-Power, High-Precision Voltage Reference
    Source
    Manufacturer datasheet

    Is it dead?

    Voltage with the board powered; ohms from each pin to ground with it off.

    Working, it reads

    Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.

    Dead, it reads

    • A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
    • Supply present, output stuck: failed, or its load has.
    On the board:
    A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
    Compare:
    The surest reference is the same IC on a working board, measured pin by pin.
    Watch for:
    Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.

    A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

    Datasheetfor REF35300QDBV, opens in a new tab
  • 23 more parts have no package on record. Nothing rules them out, so they stay.
    • CSZA51Aprinted Z51AZener diode, LRCZener diodeNot recordedLRC

      Printed Z51A. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

      What it is
      Zener diode
      Maker
      LRC
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Zener diode, VZ Min 48.45 V, VZ Nom 51 V, VZ Max 53.55 V
      Source
      Manufacturer datasheet

      Is it dead?

      Diode range for the forward check, part lifted, red probe on the anode. A bench supply for the Zener voltage.

      Working, it reads

      About 0.6 to 0.8 V forward and open in reverse on the diode range. Its Zener voltage shows only on a supply: feed it through a resistor that sets about 5 mA, cathode to positive, read quickly, and it should hold near its rated voltage.

      Dead, it reads

      • The same reading both ways round, near 0 V with a continuous beep or the same middling value: shorted.
      • Open both ways, forward too: failed open.
      • Holds well off its rated voltage on the supply test: drifted.
      • A soft knee, or a voltage that creeps on the supply test: leaky.
      On the board
      this is a first look only: the meter reads every path between those pins, and a short can be a neighbour. Lift one leg before you condemn it.
      Compare:
      If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.
      Watch for:
      A meter's diode range stops at about 2 to 3 V, so almost every Zener reads open in reverse on it, good or bad; a 3 V meter may just show a 2.4 or 2.7 V part. Above about 3 V the meter cannot tell a Zener from a plain diode.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

      Datasheetfor CSZA51A, opens in a new tab
    • MTSZ5262BWSprinted Z51VZener diode, SeCoSZener diodeNot recordedSeCoS

      Printed Z51V. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

      What it is
      Zener diode
      Maker
      SeCoS
      Package
      Not recorded
      Pins
      Not recorded
      Source
      Manufacturer datasheet

      Is it dead?

      Diode range for the forward check, part lifted, red probe on the anode. A bench supply for the Zener voltage.

      Working, it reads

      About 0.6 to 0.8 V forward and open in reverse on the diode range. Its Zener voltage shows only on a supply: feed it through a resistor that sets about 5 mA, cathode to positive, read quickly, and it should hold near its rated voltage.

      Dead, it reads

      • The same reading both ways round, near 0 V with a continuous beep or the same middling value: shorted.
      • Open both ways, forward too: failed open.
      • Holds well off its rated voltage on the supply test: drifted.
      • A soft knee, or a voltage that creeps on the supply test: leaky.
      On the board
      this is a first look only: the meter reads every path between those pins, and a short can be a neighbour. Lift one leg before you condemn it.
      Compare:
      If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.
      Watch for:
      A meter's diode range stops at about 2 to 3 V, so almost every Zener reads open in reverse on it, good or bad; a 3 V meter may just show a 2.4 or 2.7 V part. Above about 3 V the meter cannot tell a Zener from a plain diode.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

      Datasheetfor MTSZ5262BWS, opens in a new tab
    • S-CSZA51Aprinted Z51AZener diode, LRCZener diodeNot recordedLRC

      Printed Z51A. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

      What it is
      Zener diode
      Maker
      LRC
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Zener diode, VZ Min 48.45 V, VZ Nom 51 V, VZ Max 53.55 V
      Source
      Manufacturer datasheet

      Is it dead?

      Diode range for the forward check, part lifted, red probe on the anode. A bench supply for the Zener voltage.

      Working, it reads

      About 0.6 to 0.8 V forward and open in reverse on the diode range. Its Zener voltage shows only on a supply: feed it through a resistor that sets about 5 mA, cathode to positive, read quickly, and it should hold near its rated voltage.

      Dead, it reads

      • The same reading both ways round, near 0 V with a continuous beep or the same middling value: shorted.
      • Open both ways, forward too: failed open.
      • Holds well off its rated voltage on the supply test: drifted.
      • A soft knee, or a voltage that creeps on the supply test: leaky.
      On the board
      this is a first look only: the meter reads every path between those pins, and a short can be a neighbour. Lift one leg before you condemn it.
      Compare:
      If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.
      Watch for:
      A meter's diode range stops at about 2 to 3 V, so almost every Zener reads open in reverse on it, good or bad; a 3 V meter may just show a 2.4 or 2.7 V part. Above about 3 V the meter cannot tell a Zener from a plain diode.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

      Datasheetfor S-CSZA51A, opens in a new tab
    • S-CSZA51A-Sprinted Z51AZener diode, LRCZener diodeNot recordedLRC

      Printed Z51A. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

      What it is
      Zener diode
      Maker
      LRC
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Zener diode, VZ Min 48.45 V, VZ Nom 51 V, VZ Max 53.55 V
      Source
      Manufacturer datasheet

      Is it dead?

      Diode range for the forward check, part lifted, red probe on the anode. A bench supply for the Zener voltage.

      Working, it reads

      About 0.6 to 0.8 V forward and open in reverse on the diode range. Its Zener voltage shows only on a supply: feed it through a resistor that sets about 5 mA, cathode to positive, read quickly, and it should hold near its rated voltage.

      Dead, it reads

      • The same reading both ways round, near 0 V with a continuous beep or the same middling value: shorted.
      • Open both ways, forward too: failed open.
      • Holds well off its rated voltage on the supply test: drifted.
      • A soft knee, or a voltage that creeps on the supply test: leaky.
      On the board
      this is a first look only: the meter reads every path between those pins, and a short can be a neighbour. Lift one leg before you condemn it.
      Compare:
      If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.
      Watch for:
      A meter's diode range stops at about 2 to 3 V, so almost every Zener reads open in reverse on it, good or bad; a 3 V meter may just show a 2.4 or 2.7 V part. Above about 3 V the meter cannot tell a Zener from a plain diode.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

      Datasheetfor S-CSZA51A-S, opens in a new tab
    • BQ25100AYFPprinted 25100ABattery charger, 6 pins, Texas InstrumentsBattery charger6 pinsTexas Instruments

      Printed 25100A. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

      What it is
      Battery charger
      Maker
      Texas Instruments
      Package
      Not recorded
      Pins
      6
      Details
      bq2510x 250-mA Single Cell Li-Ion Battery Chargers, 1-mA Termination, 75-nA Battery Leakage
      Source
      Manufacturer datasheet

      Is it dead?

      Voltage with the board powered; ohms from each pin to ground with it off.

      Working, it reads

      Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.

      Dead, it reads

      • A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
      • Supply present, output stuck: failed, or its load has.
      On the board:
      A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
      Compare:
      The surest reference is the same IC on a working board, measured pin by pin.
      Watch for:
      Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

      Datasheetfor BQ25100AYFP, opens in a new tab
    • BQ25100HYFPprinted 25100HBattery charger, 6 pins, Texas InstrumentsBattery charger6 pinsTexas Instruments

      Printed 25100H. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

      What it is
      Battery charger
      Maker
      Texas Instruments
      Package
      Not recorded
      Pins
      6
      Details
      bq2510x 250-mA Single Cell Li-Ion Battery Chargers, 1-mA Termination, 75-nA Battery Leakage
      Source
      Manufacturer datasheet

      Is it dead?

      Voltage with the board powered; ohms from each pin to ground with it off.

      Working, it reads

      Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.

      Dead, it reads

      • A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
      • Supply present, output stuck: failed, or its load has.
      On the board:
      A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
      Compare:
      The surest reference is the same IC on a working board, measured pin by pin.
      Watch for:
      Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

      Datasheetfor BQ25100HYFP, opens in a new tab
    • BQ25100YFPprinted 25100Battery charger, 6 pins, Texas InstrumentsBattery charger6 pinsTexas Instruments

      Printed 25100. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

      What it is
      Battery charger
      Maker
      Texas Instruments
      Package
      Not recorded
      Pins
      6
      Details
      bq2510x 250-mA Single Cell Li-Ion Battery Chargers, 1-mA Termination, 75-nA Battery Leakage
      Source
      Manufacturer datasheet

      Is it dead?

      Voltage with the board powered; ohms from each pin to ground with it off.

      Working, it reads

      Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.

      Dead, it reads

      • A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
      • Supply present, output stuck: failed, or its load has.
      On the board:
      A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
      Compare:
      The surest reference is the same IC on a working board, measured pin by pin.
      Watch for:
      Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

      Datasheetfor BQ25100YFP, opens in a new tab
    • BQ25101HYFPprinted 25101HBattery charger, 6 pins, Texas InstrumentsBattery charger6 pinsTexas Instruments

      Printed 25101H. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

      What it is
      Battery charger
      Maker
      Texas Instruments
      Package
      Not recorded
      Pins
      6
      Details
      bq2510x 250-mA Single Cell Li-Ion Battery Chargers, 1-mA Termination, 75-nA Battery Leakage
      Source
      Manufacturer datasheet

      Is it dead?

      Voltage with the board powered; ohms from each pin to ground with it off.

      Working, it reads

      Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.

      Dead, it reads

      • A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
      • Supply present, output stuck: failed, or its load has.
      On the board:
      A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
      Compare:
      The surest reference is the same IC on a working board, measured pin by pin.
      Watch for:
      Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

      Datasheetfor BQ25101HYFP, opens in a new tab
    • BQ25101YFPprinted 25101Battery charger, 6 pins, Texas InstrumentsBattery charger6 pinsTexas Instruments

      Printed 25101. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

      What it is
      Battery charger
      Maker
      Texas Instruments
      Package
      Not recorded
      Pins
      6
      Details
      bq2510x 250-mA Single Cell Li-Ion Battery Chargers, 1-mA Termination, 75-nA Battery Leakage
      Source
      Manufacturer datasheet

      Is it dead?

      Voltage with the board powered; ohms from each pin to ground with it off.

      Working, it reads

      Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.

      Dead, it reads

      • A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
      • Supply present, output stuck: failed, or its load has.
      On the board:
      A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
      Compare:
      The surest reference is the same IC on a working board, measured pin by pin.
      Watch for:
      Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

      Datasheetfor BQ25101YFP, opens in a new tab
    • CSZA5.1Aprinted Z5.1AZener diode, LRCZener diodeNot recordedLRC

      Printed Z5.1A. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

      What it is
      Zener diode
      Maker
      LRC
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Zener diode, VZ Min 4.85 V, VZ Nom 5.1 V, VZ Max 5.36 V
      Source
      Manufacturer datasheet

      Is it dead?

      Diode range for the forward check, part lifted, red probe on the anode. A bench supply for the Zener voltage.

      Working, it reads

      About 0.6 to 0.8 V forward and open in reverse on the diode range. Its Zener voltage shows only on a supply: feed it through a resistor that sets about 5 mA, cathode to positive, read quickly, and it should hold near its rated voltage.

      Dead, it reads

      • The same reading both ways round, near 0 V with a continuous beep or the same middling value: shorted.
      • Open both ways, forward too: failed open.
      • Holds well off its rated voltage on the supply test: drifted.
      • A soft knee, or a voltage that creeps on the supply test: leaky.
      On the board
      this is a first look only: the meter reads every path between those pins, and a short can be a neighbour. Lift one leg before you condemn it.
      Compare:
      If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.
      Watch for:
      A meter's diode range stops at about 2 to 3 V, so almost every Zener reads open in reverse on it, good or bad; a 3 V meter may just show a 2.4 or 2.7 V part. Above about 3 V the meter cannot tell a Zener from a plain diode.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

      Datasheetfor CSZA5.1A, opens in a new tab
    • ESD25CT8printed 2512PESD protection diode, LeiditechESD protection diodeNot recordedLeiditech

      Printed 2512P. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

      What it is
      ESD protection diode
      Maker
      Leiditech
      Package
      Not recorded
      Pins
      Not recorded
      Details
      ESD protection diode, VRWM 2.5 V, Cj 8 pF
      Source
      Manufacturer datasheet

      Is it dead?

      Diode range, from the protected line to ground, part lifted if you can.

      Working, it reads

      A one-way part reads about 0.6 to 0.8 V forward and open in reverse. A two-way part reads open both ways. Arrays with several lines read as the datasheet's diagram draws them.

      Dead, it reads

      • From the line to ground, the same reading both ways, near 0 V with a continuous beep: shorted.
      • A reading both ways on a one-way part: leaky.
      • A one-way part open both ways: failed open.
      On the board
      , a line reading shorted to ground can be this part or anything else on that line. Lift it: if the short goes with it, it has failed.
      Compare:
      The same part on the next line or connector pin is the healthy reading to compare with.
      Watch for:
      A two-way part reads open both ways when it is good, exactly like one that has failed open. The meter cannot tell them apart; an identical part on the next line can.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

      Datasheetfor ESD25CT8, opens in a new tab
    • G2514AUG1Uprinted 2514A28 pins, Global Mixed-mode TechnologyNot recorded28 pinsGlobal Mixed-mode Technology

      Printed 2514A. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

      What it is
      Not recorded
      Maker
      Global Mixed-mode Technology
      Package
      Not recorded
      Pins
      28
      Details
      G2514A Integrated Power Supply for TFT-LCD
      Source
      Manufacturer datasheet

      Is it dead?

      Diode range and ohms range, part lifted.

      Working, it reads

      Depends on what it is. The datasheet, or an identical part, says.

      Dead, it reads

      • Between two pins, the same reading both ways, near 0 V with a continuous beep: shorted.
      • Open between every pair of pins: failed open, or a part that reads open when working.
      On the board
      this is a first look only: the meter reads every path between those pins, and a short can be a neighbour. Lift one leg before you condemn it.
      Compare:
      If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

      Datasheetfor G2514AUG1U, opens in a new tab
    • G2517AKM1Uprinted 2517A24 pins, Global Mixed-mode TechnologyNot recorded24 pinsGlobal Mixed-mode Technology

      Printed 2517A. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

      What it is
      Not recorded
      Maker
      Global Mixed-mode Technology
      Package
      Not recorded
      Pins
      24
      Details
      G2517A Integrated Power Supply for TFT-LCD
      Source
      Manufacturer datasheet

      Is it dead?

      Diode range and ohms range, part lifted.

      Working, it reads

      Depends on what it is. The datasheet, or an identical part, says.

      Dead, it reads

      • Between two pins, the same reading both ways, near 0 V with a continuous beep: shorted.
      • Open between every pair of pins: failed open, or a part that reads open when working.
      On the board
      this is a first look only: the meter reads every path between those pins, and a short can be a neighbour. Lift one leg before you condemn it.
      Compare:
      If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

      Datasheetfor G2517AKM1U, opens in a new tab
    • G2518KK1Uprinted 251840 pins, Global Mixed-mode TechnologyNot recorded40 pinsGlobal Mixed-mode Technology

      Printed 2518. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

      What it is
      Not recorded
      Maker
      Global Mixed-mode Technology
      Package
      Not recorded
      Pins
      40
      Details
      G2518 Integrated Power Supply for TFT-LCD
      Source
      Manufacturer datasheet

      Is it dead?

      Diode range and ohms range, part lifted.

      Working, it reads

      Depends on what it is. The datasheet, or an identical part, says.

      Dead, it reads

      • Between two pins, the same reading both ways, near 0 V with a continuous beep: shorted.
      • Open between every pair of pins: failed open, or a part that reads open when working.
      On the board
      this is a first look only: the meter reads every path between those pins, and a short can be a neighbour. Lift one leg before you condemn it.
      Compare:
      If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

      Datasheetfor G2518KK1U, opens in a new tab
    • MTSZ5251CWprinted 251CZener diode, SeCoSZener diodeNot recordedSeCoS

      Printed 251C. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

      What it is
      Zener diode
      Maker
      SeCoS
      Package
      Not recorded
      Pins
      Not recorded
      Source
      Manufacturer datasheet

      Is it dead?

      Diode range for the forward check, part lifted, red probe on the anode. A bench supply for the Zener voltage.

      Working, it reads

      About 0.6 to 0.8 V forward and open in reverse on the diode range. Its Zener voltage shows only on a supply: feed it through a resistor that sets about 5 mA, cathode to positive, read quickly, and it should hold near its rated voltage.

      Dead, it reads

      • The same reading both ways round, near 0 V with a continuous beep or the same middling value: shorted.
      • Open both ways, forward too: failed open.
      • Holds well off its rated voltage on the supply test: drifted.
      • A soft knee, or a voltage that creeps on the supply test: leaky.
      On the board
      this is a first look only: the meter reads every path between those pins, and a short can be a neighbour. Lift one leg before you condemn it.
      Compare:
      If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.
      Watch for:
      A meter's diode range stops at about 2 to 3 V, so almost every Zener reads open in reverse on it, good or bad; a 3 V meter may just show a 2.4 or 2.7 V part. Above about 3 V the meter cannot tell a Zener from a plain diode.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

      Datasheetfor MTSZ5251CW, opens in a new tab
    • MTSZ5251CWSprinted 251CZener diode, SeCoSZener diodeNot recordedSeCoS

      Printed 251C. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

      What it is
      Zener diode
      Maker
      SeCoS
      Package
      Not recorded
      Pins
      Not recorded
      Source
      Manufacturer datasheet

      Is it dead?

      Diode range for the forward check, part lifted, red probe on the anode. A bench supply for the Zener voltage.

      Working, it reads

      About 0.6 to 0.8 V forward and open in reverse on the diode range. Its Zener voltage shows only on a supply: feed it through a resistor that sets about 5 mA, cathode to positive, read quickly, and it should hold near its rated voltage.

      Dead, it reads

      • The same reading both ways round, near 0 V with a continuous beep or the same middling value: shorted.
      • Open both ways, forward too: failed open.
      • Holds well off its rated voltage on the supply test: drifted.
      • A soft knee, or a voltage that creeps on the supply test: leaky.
      On the board
      this is a first look only: the meter reads every path between those pins, and a short can be a neighbour. Lift one leg before you condemn it.
      Compare:
      If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.
      Watch for:
      A meter's diode range stops at about 2 to 3 V, so almost every Zener reads open in reverse on it, good or bad; a 3 V meter may just show a 2.4 or 2.7 V part. Above about 3 V the meter cannot tell a Zener from a plain diode.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

      Datasheetfor MTSZ5251CWS, opens in a new tab
    • S-CSZA5.1Aprinted Z5.1AZener diode, LRCZener diodeNot recordedLRC

      Printed Z5.1A. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

      What it is
      Zener diode
      Maker
      LRC
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Zener diode, VZ Min 4.85 V, VZ Nom 5.1 V, VZ Max 5.36 V
      Source
      Manufacturer datasheet

      Is it dead?

      Diode range for the forward check, part lifted, red probe on the anode. A bench supply for the Zener voltage.

      Working, it reads

      About 0.6 to 0.8 V forward and open in reverse on the diode range. Its Zener voltage shows only on a supply: feed it through a resistor that sets about 5 mA, cathode to positive, read quickly, and it should hold near its rated voltage.

      Dead, it reads

      • The same reading both ways round, near 0 V with a continuous beep or the same middling value: shorted.
      • Open both ways, forward too: failed open.
      • Holds well off its rated voltage on the supply test: drifted.
      • A soft knee, or a voltage that creeps on the supply test: leaky.
      On the board
      this is a first look only: the meter reads every path between those pins, and a short can be a neighbour. Lift one leg before you condemn it.
      Compare:
      If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.
      Watch for:
      A meter's diode range stops at about 2 to 3 V, so almost every Zener reads open in reverse on it, good or bad; a 3 V meter may just show a 2.4 or 2.7 V part. Above about 3 V the meter cannot tell a Zener from a plain diode.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

      Datasheetfor S-CSZA5.1A, opens in a new tab
    • SGM25117AXTGM12Gprinted 25117Load switch, 12 pins, SG MicroLoad switch12 pinsSG Micro

      Printed 25117. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

      What it is
      Load switch
      Maker
      SG Micro
      Package
      Not recorded
      Pins
      12
      Details
      Ultra-Low RON, Advanced Load Management Controlled Load Switch
      Source
      Manufacturer datasheet

      Is it dead?

      Voltage, board powered, black probe on ground.

      Working, it reads

      Switched on, the output pin sits at the input voltage. Switched off, it sits near 0 V.

      Dead, it reads

      • Output at the input voltage while switched off: the pass element has shorted.
      • Input present and switched on, no output: failed open, or shut down into a shorted load. Power off and measure output to ground.
      On the board:
      An output near 0 Ω to ground is usually the load. Lift the output pin to see which.
      Compare:
      If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.
      Watch for:
      The pinout and whether the enable is active high or low differ between parts. The datasheet gives both.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

      Datasheetfor SGM25117AXTGM12G, opens in a new tab
    • LR32515BG-AG6printed 2515GLDO regulator, UnisonicLDO regulatorNot recordedUnisonic

      Printed 2515G. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

      What it is
      LDO regulator
      Maker
      Unisonic
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Linear voltage regulator IC: LDO, Dual out, Vout1/Vout2=2.5V/1.5V±0.5%, 150mA, +CE, H-free
      Source
      Published code list

      Is it dead?

      Voltage, board powered, black probe on ground. Then ohms with the power off.

      Working, it reads

      Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

      Dead, it reads

      • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
      • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
      • Power off, input to output near 0 Ω: shorted.
      On the board:
      An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
      Compare:
      The same regulator on another rail or another board shows the right voltages and the right resistances.
      Watch for:
      Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

    • LR32515BL-AG6printed 2515LLDO regulator, UnisonicLDO regulatorNot recordedUnisonic

      Printed 2515L. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

      What it is
      LDO regulator
      Maker
      Unisonic
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Linear voltage regulator IC: LDO, Dual out, Vout1/Vout2=2.5V/1.5V±0.5%, 150mA, +CE, L-free
      Source
      Published code list

      Is it dead?

      Voltage, board powered, black probe on ground. Then ohms with the power off.

      Working, it reads

      Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

      Dead, it reads

      • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
      • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
      • Power off, input to output near 0 Ω: shorted.
      On the board:
      An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
      Compare:
      The same regulator on another rail or another board shows the right voltages and the right resistances.
      Watch for:
      Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

    • LR32516BG-AG6printed 2516GLDO regulator, UnisonicLDO regulatorNot recordedUnisonic

      Printed 2516G. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

      What it is
      LDO regulator
      Maker
      Unisonic
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Linear voltage regulator IC: LDO, Dual out, Vout1/Vout2=2.5V/1.6V±0.5%, 150mA, +CE, H-free
      Source
      Published code list

      Is it dead?

      Voltage, board powered, black probe on ground. Then ohms with the power off.

      Working, it reads

      Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

      Dead, it reads

      • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
      • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
      • Power off, input to output near 0 Ω: shorted.
      On the board:
      An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
      Compare:
      The same regulator on another rail or another board shows the right voltages and the right resistances.
      Watch for:
      Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

    • LR32516BL-AG6printed 2516LLDO regulator, UnisonicLDO regulatorNot recordedUnisonic

      Printed 2516L. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

      What it is
      LDO regulator
      Maker
      Unisonic
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Linear voltage regulator IC: LDO, Dual out, Vout1/Vout2=2.5V/1.6V±0.5%, 150mA, +CE, L-free
      Source
      Published code list

      Is it dead?

      Voltage, board powered, black probe on ground. Then ohms with the power off.

      Working, it reads

      Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

      Dead, it reads

      • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
      • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
      • Power off, input to output near 0 Ω: shorted.
      On the board:
      An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
      Compare:
      The same regulator on another rail or another board shows the right voltages and the right resistances.
      Watch for:
      Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

    • LR32517BG-AG6printed 2517GLDO regulator, UnisonicLDO regulatorNot recordedUnisonic

      Printed 2517G. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

      What it is
      LDO regulator
      Maker
      Unisonic
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Linear voltage regulator IC: LDO, Dual out, Vout1/Vout2=2.5V/1.7V±0.5%, 150mA, +CE, H-free
      Source
      Published code list

      Is it dead?

      Voltage, board powered, black probe on ground. Then ohms with the power off.

      Working, it reads

      Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

      Dead, it reads

      • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
      • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
      • Power off, input to output near 0 Ω: shorted.
      On the board:
      An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
      Compare:
      The same regulator on another rail or another board shows the right voltages and the right resistances.
      Watch for:
      Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

      A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

5 more parts are not listed here. Type more of the code to narrow the list.

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One code, several parts

Marking codes are not unique. In the standard code book, 6H on a SOT-23 is an NPN transistor, a varicap, an N-channel JFET, two digital transistors, a 3.6 V voltage detector: six parts from five makers. So a search on WhatSMD (What SMD) shows the parts we hold under that code and under codes easily misread as it, with only the columns that tell them apart.

6Hon a SOT-23, in the code book
  • NPN transistor
  • Varicap
  • N-channel JFET
  • Digital transistor ×2
  • 3.6 V voltage detector

When more than one is left

Tap Help me choose. Up to 4 quick answers: whether the part has failed, then what separates the parts left. Those get ranked with the reasoning and a test that settles it. That uses one identification: 2 a month are free without an account, and 3 with a free account.

When you cannot read it

Tap the camera in the field. We read the characters, keep the ones we are unsure of, and search every reading. A photo too soft to read is turned back on your phone first; if it is the only one you can get, you can still send it.

Get the app

The same search on your phone, and a camera with a light, zoom and tap to focus for a marking you cannot read. Sign in with your email address to use the same account.

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