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SMD code TF in SMB

Marking codes are not standardised, and the same code is reused by unrelated makers for unrelated parts. Below is every part in our tables printed with it, and any printed with a code that is easy to misread as it, from the manufacturers' own marking tables and published code lists.

Not sure which one you have?

Answer up to 4 quick questions and these 22 parts are ranked, with a meter test that settles it. It works on a dead part too.

  • P6SMB51CSMB2 pins, FagNot recorded2 pinsFag
    What it is
    Not recorded
    Maker
    Fag
    Package
    SMB
    Pins
    2
    Details
    TVS: 51V, 8,2A, 600W(1ms), Bidirectional
    Source
    Published code list

    Is it dead? The meter test is below: TVS or ESD protection diode.

  • 14 more parts have no package on record. Nothing rules them out, so they stay.
    • LNTA4001NT1GN-channel MOSFET, LRCN-channel MOSFETNot recordedLRC
      What it is
      N-channel MOSFET
      Maker
      LRC
      Package
      Not recorded
      Pins
      Not recorded
      Details
      MOSFET, N-Channel(with ESD), VDSS 20 V, VGS 10 V
      Source
      Manufacturer datasheet

      Is it dead? The meter test is below: N-channel MOSFET.

    • NCP105AMX280LDO regulator, onsemiLDO regulatorNot recordedonsemi
      What it is
      LDO regulator
      Maker
      onsemi
      Package
      Not recorded
      Pins
      Not recorded
      Details
      LDO Regulator - High PSRR
      Source
      Manufacturer datasheet

      Is it dead? The meter test is below: Voltage regulator.

    • NCV8177AMTW330LDO regulator, onsemiLDO regulatorNot recordedonsemi
      What it is
      LDO regulator
      Maker
      onsemi
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Linear Voltage Regulator, Fast Transient Response, 500 mA with Enable
      Source
      Manufacturer datasheet

      Is it dead? The meter test is below: Voltage regulator.

    • S-LNTA4001NT1GN-channel MOSFET, LRCN-channel MOSFETNot recordedLRC
      What it is
      N-channel MOSFET
      Maker
      LRC
      Package
      Not recorded
      Pins
      Not recorded
      Details
      MOSFET, N-Channel(with ESD), VDSS 20 V, VGS 10 V
      Source
      Manufacturer datasheet

      Is it dead? The meter test is below: N-channel MOSFET.

    • MTA2K5N03KFEN-channel MOSFET, CYStekN-channel MOSFETNot recordedCYStek
      What it is
      N-channel MOSFET
      Maker
      CYStek
      Package
      Not recorded
      Pins
      Not recorded
      Details
      30 V, 0.39 A N-channel MOSFET
      Source
      Manufacturer datasheet

      Is it dead? The meter test is below: N-channel MOSFET.

    • 74HCT1G14GWNXPNot recordedNot recordedNXP
      What it is
      Not recorded
      Maker
      NXP
      Package
      Not recorded
      Pins
      Not recorded
      Details
      CMOS logic IC: Inverter with Schmitt-trigger input
      Source
      Published code list

      Is it dead? The meter test is below: Integrated circuit.

    • AP7341-11FS4-7LDO regulator, Diodes IncorporatedLDO regulatorNot recordedDiodes Incorporated
      What it is
      LDO regulator
      Maker
      Diodes Incorporated
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Linear voltage regulator IC: LDO, 1.1V±1%, 300mA, +CE
      Source
      Published code list

      Is it dead? The meter test is below: Voltage regulator.

    • BD45335GVoltage supervisor, ROHMVoltage supervisorNot recordedROHM
      What it is
      Voltage supervisor
      Maker
      ROHM
      Package
      Not recorded
      Pins
      Not recorded
      Details
      CMOS-IC: Voltage Detector 3,3V, -Reset Open drain output, 500ms
      Source
      Published code list

      Is it dead? The meter test is below: Integrated circuit.

    • IXD5127C26HNRVoltage supervisor, IXYSVoltage supervisorNot recordedIXYS
      What it is
      Voltage supervisor
      Maker
      IXYS
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Voltage detector IC: 2.6V±0.8%, +Reset PPO, -MR, 200ms Rt delay
      Source
      Published code list

      Is it dead? The meter test is below: Integrated circuit.

    • KDZ36FVZener diode, KECZener diodeNot recordedKEC
      What it is
      Zener diode
      Maker
      KEC
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Zener diode: 34.0..38.0V, Izt=2mA, Zzt=300, 100mW
      Source
      Published code list

      Is it dead? The meter test is below: Zener diode.

    • TC75S59FComparator, ToshibaComparatorNot recordedToshiba
      What it is
      Comparator
      Maker
      Toshiba
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Voltage comparator IC: CMOS, Vcc=±3.5..±7V, Icc0=200µA, Iout=±35mA
      Source
      Published code list

      Is it dead? The meter test is below: Integrated circuit.

    • TC75S59FEComparator, ToshibaComparatorNot recordedToshiba
      What it is
      Comparator
      Maker
      Toshiba
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Voltage comparator IC: CMOS, Vcc=±3.5..±7V, Icc0=200µA, Iout=±35mA
      Source
      Published code list

      Is it dead? The meter test is below: Integrated circuit.

    • TC75S59FUComparator, ToshibaComparatorNot recordedToshiba
      What it is
      Comparator
      Maker
      Toshiba
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Voltage comparator IC: CMOS, Vcc=±3.5..±7V, Icc0=200µA, Iout=±35mA
      Source
      Published code list

      Is it dead? The meter test is below: Integrated circuit.

    • uPA1914TEP-channel MOSFET, NEC ElectronicsP-channel MOSFETNot recordedNEC Electronics
      What it is
      P-channel MOSFET
      Maker
      NEC Electronics
      Package
      Not recorded
      Pins
      Not recorded
      Details
      MOSFET p-type: V-MOS, LogL, 30V, ±4.5A, 200mW,<96m(2.5A)
      Source
      Published code list

      Is it dead? The meter test is below: P-channel MOSFET.

Is it dead? One meter test per kind

Parts of the same kind are tested the same way, so each test is here once. Each part above points to its own.

TVS or ESD protection diode

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.

N-channel MOSFET

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.

Voltage regulator

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.

Integrated circuit

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.

Zener diode

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.

P-channel MOSFET

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

Working, it reads

Red probe on the drain, black on the source: 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. 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.

Printed with a code easy to misread as TF

One character differs, and it is one that is easy to confuse under a lamp. Each code has a page of its own.

Codes that begin with TF

For a marking with its end worn or burnt off. Each code has a page of its own.

Codes not listed here are printed on 12 more parts.

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