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SMD code ALP

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.

14 parts are printed ALP

Not sure which one you have?

Answer up to 4 quick questions and these 14 parts are ranked, with a meter test that settles it. It works on a dead part too.

  • 1.0SMBJ16ASMBTVS diode, 2 pins, SOCAYTVS diodeSMB2 pinsSOCAY
    What it is
    TVS diode
    Maker
    SOCAY
    Package
    SMB
    Pins
    2
    Source
    Manufacturer datasheet

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

  • SMB10J16ASMBTVS diode, 2 pins, DOWOTVS diodeSMB2 pinsDOWO
    What it is
    TVS diode
    Maker
    DOWO
    Package
    SMB
    Pins
    2
    Source
    Manufacturer datasheet

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

  • TVJ10B160J-HFSMBTVS diode, 2 pins, ComchipTVS diodeSMB2 pinsComchip
    What it is
    TVS diode
    Maker
    Comchip
    Package
    SMB
    Pins
    2
    Details
    16 V 1000 W unidirectional TVS diode
    Source
    Manufacturer datasheet

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

  • 2SA1900-PSOT-89PNP transistor, 3 pins, ROHMPNP transistorSOT-893 pinsROHM
    What it is
    PNP transistor
    Maker
    ROHM
    Package
    SOT-89
    Pins
    3
    Details
    Si-pnp: Lo-sat, 60V, 1A, 500mW, B=82..180, >150MHz
    Source
    Published code list

    Is it dead? The meter test is below: PNP transistor.

  • 2SC3802K-PSOT-23NPN transistor, 3 pins, ROHMNPN transistorSOT-233 pinsROHM
    What it is
    NPN transistor
    Maker
    ROHM
    Package
    SOT-23
    Pins
    3
    Details
    Si-npn: AF, 30V, 30mA, 200mW, B=82..180, >110MHz
    Source
    Published code list

    Is it dead? The meter test is below: NPN transistor.

  • LM4040CEX3-3.0SOT-323Voltage reference, 3 pins, Analog DevicesVoltage referenceSOT-3233 pinsAnalog Devices
    What it is
    Voltage reference
    Maker
    Analog Devices
    Package
    SOT-323
    Pins
    3
    Details
    Voltage reference IC: uPower, Precision, Shunt, 3.00V±0.5%
    Source
    Published code list

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

  • SMAJ7.0CSMATVS diode, 2 pins, BytesonicTVS diodeSMA2 pinsBytesonic
    What it is
    TVS diode
    Maker
    Bytesonic
    Package
    SMA
    Pins
    2
    Source
    Published code list

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

  • TC1302ALPVMFDFNLDO regulator, MicrochipLDO regulatorDFNNot recordedMicrochip
    What it is
    LDO regulator
    Maker
    Microchip
    Package
    DFN
    Pins
    Not recorded
    Details
    Linear voltage regulator IC: LDO, Dual out, Vo1/Vo2=2.2V(300mA)/1.8V(150mA)±2.5%, +CE
    Source
    Published code list

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

  • TPSMA9.1SMATVS diode, 2 pins, VishayTVS diodeSMA2 pinsVishay
    What it is
    TVS diode
    Maker
    Vishay
    Package
    SMA
    Pins
    2
    Details
    TVS: 9,1V, 29A, 400W (1ms)
    Source
    Published code list

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

  • TVJ10B160J(B)-HSMBTVS diode, 2 pins, ComchipTVS diodeSMB2 pinsComchip
    What it is
    TVS diode
    Maker
    Comchip
    Package
    SMB
    Pins
    2
    Details
    Transient voltage supressor: Vbr=17.8..19.7V, Vrwm=16.0V, Ipp=38.46A, 1000W(1ms)
    Source
    Published code list

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

  • XC6114D522MRSOT-23-5Voltage supervisor, 5 pins, TorexVoltage supervisorSOT-23-55 pinsTorex
    What it is
    Voltage supervisor
    Maker
    Torex
    Package
    SOT-23-5
    Pins
    5
    Details
    CMOS-IC: VDet 2.2V, ±Reset PPO, Wt=400ms, Rt=100ms
    Source
    Published code list

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

  • 3 more parts have no package on record
    • TLV431ALPRAGVoltage reference, onsemiVoltage referenceNot recordedNot recordedonsemi
      What it is
      Voltage reference
      Maker
      onsemi
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Low Voltage Precision Adjustable Shunt Regulator
      Source
      Manufacturer datasheet

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

    • TPSMP9.1TVS diode, VishayTVS diodeNot recordedNot recordedVishay
      What it is
      TVS diode
      Maker
      Vishay
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Transient voltage supressor: Vbr=8.19..10.0V, Vrwm=7.37V, Ipp=21.7A, 300W(1ms)
      Source
      Published code list

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

    • XC6501P22AHR-GLDO regulator, TorexLDO regulatorNot recordedNot recordedTorex
      What it is
      LDO regulator
      Maker
      Torex
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Linear voltage regulator IC: LDO, 2.25V±1%, 200mA
      Source
      Published code list

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

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.

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.

PNP transistor

Diode range, part lifted or its base leg off the pad.

Working, it reads

Black probe on the base reads about 0.6 to 0.75 V to the emitter and to the collector, and open the other way round. Collector to emitter reads open both ways.

Dead, it reads

  • Collector to emitter the same both ways, near 0 V with a continuous beep: shorted. The commonest failure.
  • The base the same both ways to another pin, near 0 V or a middling value: a shorted junction.
  • Only one junction reads, or none: a junction has failed open. It then looks like a diode.
  • A reading the wrong way round, where it should be open: 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 pair of diodes with a common pin reads just like a transistor, and some transistors carry a built-in diode or resistor. The datasheet says which.

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

NPN transistor

Diode range, part lifted or its base leg off the pad.

Working, it reads

Red probe on the base reads about 0.6 to 0.75 V to the emitter and to the collector, and open the other way round. Collector to emitter reads open both ways.

Dead, it reads

  • Collector to emitter the same both ways, near 0 V with a continuous beep: shorted. The commonest failure.
  • The base the same both ways to another pin, near 0 V or a middling value: a shorted junction.
  • Only one junction reads, or none: a junction has failed open. It then looks like a diode.
  • A reading the wrong way round, where it should be open: 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 pair of diodes with a common pin reads just like a transistor, and some transistors carry a built-in diode or resistor. The datasheet says which.

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.

Printed with a code easy to misread as ALP

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 ALP

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

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