10 Ω resistor. 1 part is printed 100. 5 printed with a similar-looking code.
100 on a chip resistor
10 Ω
10 Ω resistor, 5%
10 followed by 0 zeros. Three digits is normally the 5% series. The same marking also reads as 10 pF on a capacitor or 10 µH on an inductor, and nothing in the code says which; the body of the part does.
The same characters on another part
- 10 pF capacitor
- 10 µH inductor
Check it with a meter
Lift one end and measure across it. A good one reads 10 Ω within 5%. Measuring it in circuit reads the parallel combination of everything around it, which is almost always lower, never higher: well above 10 Ω on the board is a fault. Open, or well above 10 Ω, means it has failed: burnt, cracked or corroded. That does not change what to fit: the marking still says 10 Ω. A burnt resistor usually means the part it feeds drew too much, so find that before fitting a new one.
On a transistor or diode body (SOT-23-5, SOT-23, SMA), 100 is a part code instead. Those parts are listed below.
Not sure which one you have?
Answer up to 4 quick questions and these 6 parts are ranked, with a meter test that settles it. It works on a dead part too.
The only part printed 100 in our tables
SML4764
- What it is
- Zener diode
- Maker
- Vishay
- Package
- SMA
- Pins
- 2
- Details
- 100 V Zener diode
- Source
- From the manufacturer's 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:
- 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.
Printed with a code easy to misread
These parts are printed with a character that is easy to misread as what you typed. The odd one out is marked on each.
LM3480IM3-15printed L0DSOT-23LDO regulator, 3 pins, Texas InstrumentsLDO regulatorSOT-233 pinsTexas Instruments
Printed L0D on the part. Easy to misread as 100. Check that character with a loupe before you order anything.
- What it is
- LDO regulator
- Maker
- Texas Instruments
- Package
- SOT-23
- Pins
- 3
- Details
- 100-mA, SOT-23, Quasi Low-Dropout Linear Voltage Regulator
- Source
- From the manufacturer's 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.
LM3480IM3X-15printed L0DSOT-23LDO regulator, 3 pins, Texas InstrumentsLDO regulatorSOT-233 pinsTexas Instruments
Printed L0D on the part. Easy to misread as 100. Check that character with a loupe before you order anything.
- What it is
- LDO regulator
- Maker
- Texas Instruments
- Package
- SOT-23
- Pins
- 3
- Details
- 100-mA, SOT-23, Quasi Low-Dropout Linear Voltage Regulator
- Source
- From the manufacturer's 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.
SN74AHCT1G00DCKprinted 1QOSOT-353Logic gate, 5 pins, Texas InstrumentsLogic gateSOT-3535 pinsTexas Instruments
Printed 1QO on the part. Easy to misread as 100. Check that character with a loupe before you order anything.
- What it is
- Logic gate
- Maker
- Texas Instruments
- Package
- SOT-353
- Pins
- 5
- Details
- Single 2-Input Positive-NAND Gate
- Source
- From the manufacturer's 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.
SN74LV1T125DCKprinted 1QQSOT-353Logic gate, 5 pins, Texas InstrumentsLogic gateSOT-3535 pinsTexas Instruments
Printed 1QQ on the part. Easy to misread as 100. Check that character with a loupe before you order anything.
- What it is
- Logic gate
- Maker
- Texas Instruments
- Package
- SOT-353
- Pins
- 5
- Details
- Single Power Supply Single Buffer Gate with 3-State Output CMOS Logic Level Shifter
- Source
- From the manufacturer's 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.
1 more part has no package on record
PLZ10Dprinted 10DZener diode, VishayZener diodeNot recordedNot recordedVishay
Printed 10D on the part. Easy to misread as 100. Check that character with a loupe before you order anything.
- What it is
- Zener diode
- Maker
- Vishay
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 10 V Zener diode
- Source
- From the manufacturer's 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:
- 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.
13 more parts have codes that begin with 100
Codes that begin with 100
For a marking with its end worn or burnt off. Each one shows its full printed code.
1.5SMC100Aprinted 100ASMCTVS diode, 2 pins, VishayTVS diodeSMC2 pinsVishay
Printed 100A. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.
- What it is
- TVS diode
- Maker
- Vishay
- Package
- SMC
- Pins
- 2
- Source
- From the manufacturer's 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:
- 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.
1.5SMC100CAprinted 100CSMCTVS diode, 2 pins, VishayTVS diodeSMC2 pinsVishay
Printed 100C. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.
- What it is
- TVS diode
- Maker
- Vishay
- Package
- SMC
- Pins
- 2
- Details
- 1500 W TVS diode, bidirectional
- Source
- From the manufacturer's 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:
- 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.
SML4764Aprinted 100ASMAZener diode, 2 pins, VishayZener diodeSMA2 pinsVishay
Printed 100A. 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
- Vishay
- Package
- SMA
- Pins
- 2
- Details
- 100 V Zener diode
- Source
- From the manufacturer's 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:
- 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.
LP2980AIM5-3.3printed L00ASOT-23-5LDO regulator, 5 pins, Texas InstrumentsLDO regulatorSOT-23-55 pinsTexas Instruments
Printed L00A. 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
- Texas Instruments
- Package
- SOT-23-5
- Pins
- 5
- Details
- Micropower, 50mA, Ultra-Low Dropout Regulator in SOT-23 Package
- Source
- From the manufacturer's 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.
LP2980AIM5X-3.3printed L00ASOT-23-5LDO regulator, 5 pins, Texas InstrumentsLDO regulatorSOT-23-55 pinsTexas Instruments
Printed L00A. 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
- Texas Instruments
- Package
- SOT-23-5
- Pins
- 5
- Details
- Micropower, 50mA, Ultra-Low Dropout Regulator in SOT-23 Package
- Source
- From the manufacturer's 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.
LP2980IM5-3.3printed L00BSOT-23-5LDO regulator, 5 pins, Texas InstrumentsLDO regulatorSOT-23-55 pinsTexas Instruments
Printed L00B. 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
- Texas Instruments
- Package
- SOT-23-5
- Pins
- 5
- Details
- Micropower, 50mA, Ultra-Low Dropout Regulator in SOT-23 Package
- Source
- From the manufacturer's 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.
LP2980IM5X-3.3printed L00BSOT-23-5LDO regulator, 5 pins, Texas InstrumentsLDO regulatorSOT-23-55 pinsTexas Instruments
Printed L00B. 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
- Texas Instruments
- Package
- SOT-23-5
- Pins
- 5
- Details
- Micropower, 50mA, Ultra-Low Dropout Regulator in SOT-23 Package
- Source
- From the manufacturer's 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.
LP3985IM5-3.3printed LDQBSOT-23-5LDO regulator, 5 pins, Texas InstrumentsLDO regulatorSOT-23-55 pinsTexas Instruments
Printed LDQB. 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
- Texas Instruments
- Package
- SOT-23-5
- Pins
- 5
- Details
- Micropower, 150-mA Low-Noise Ultra-Low-Dropout CMOS Voltage Regulator
- Source
- From the manufacturer's 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.
LP3985IM5X-3.3printed LDQBSOT-23-5LDO regulator, 5 pins, Texas InstrumentsLDO regulatorSOT-23-55 pinsTexas Instruments
Printed LDQB. 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
- Texas Instruments
- Package
- SOT-23-5
- Pins
- 5
- Details
- Micropower, 150-mA Low-Noise Ultra-Low-Dropout CMOS Voltage Regulator
- Source
- From the manufacturer's 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.
TLV9001UIDBVprinted 1ODFSOT-23-5Operational amplifier, 5 pins, Texas InstrumentsOperational amplifierSOT-23-55 pinsTexas Instruments
Printed 1ODF. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.
- What it is
- Operational amplifier
- Maker
- Texas Instruments
- Package
- SOT-23-5
- Pins
- 5
- Details
- Low-Power, RRIO, 1-MHz Operational Amplifier for Cost-Sensitive Systems
- Source
- From the manufacturer's 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.
TLV74130PDBVprinted 1DOTSOT-23-5LDO regulator, 5 pins, Texas InstrumentsLDO regulatorSOT-23-55 pinsTexas Instruments
Printed 1DOT. 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
- Texas Instruments
- Package
- SOT-23-5
- Pins
- 5
- Details
- 150-mA, Low-Dropout Regulator With Foldback Current Limit
- Source
- From the manufacturer's 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.
TPS7A0512PDBZprinted 1QOWSOT-23LDO regulator, 3 pins, Texas InstrumentsLDO regulatorSOT-233 pinsTexas Instruments
Printed 1QOW. 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
- Texas Instruments
- Package
- SOT-23
- Pins
- 3
- Details
- 1-µA Ultralow IQ, 200-mA, Low-Dropout Regulator in a Small-Size Package
- Source
- From the manufacturer's 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.
TPS7A0518PDBZprinted 1QQWSOT-23LDO regulator, 3 pins, Texas InstrumentsLDO regulatorSOT-233 pinsTexas Instruments
Printed 1QQW. 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
- Texas Instruments
- Package
- SOT-23
- Pins
- 3
- Details
- 1-µA Ultralow IQ, 200-mA, Low-Dropout Regulator in a Small-Size Package
- Source
- From the manufacturer's 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.
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 shows the parts we hold under that code and under codes easily misread as it, with only the columns that tell them apart.
- 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.