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SMD code XP in SOT-23

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 29 parts are ranked, with a meter test that settles it. It works on a dead part too.

  • FMBTRC107SSSOT-23Digital transistor (NPN, resistors built in), 3 pins, Formosa MicrosemiDigital transistor (NPN, resistors built in)3 pinsFormosa Microsemi
    What it is
    Digital transistor (NPN, resistors built in)
    Maker
    Formosa Microsemi
    Package
    SOT-23
    Pins
    3
    Source
    Manufacturer datasheet

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

  • 12A01CSOT-233 pins, Sanyo ElectricNot recorded3 pinsSanyo Electric
    What it is
    Not recorded
    Maker
    Sanyo Electric
    Package
    SOT-23
    Pins
    3
    Details
    pnp gp amp 15V 0.5A comp 15C01M hfe 300-700
    Source
    Published code list

    Is it dead? The meter test is below: This part.

  • BZX99-C3V3SOT-233 pins, NXPNot recorded3 pinsNXP
    What it is
    Not recorded
    Maker
    NXP
    Package
    SOT-23
    Pins
    3
    Details
    3.3V 0.3W zener
    Source
    Published code list

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

  • MMBD3000SOT-233 pins, MotorolaNot recorded3 pinsMotorola
    What it is
    Not recorded
    Maker
    Motorola
    Package
    SOT-23
    Pins
    3
    Details
    Si diode 30V 0.2A
    Source
    Published code list

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

  • MMBD3000T1SOT-233 pins, onsemiNot recorded3 pinsonsemi
    What it is
    Not recorded
    Maker
    onsemi
    Package
    SOT-23
    Pins
    3
    Source
    Published code list

    Is it dead? The meter test is below: This part.

  • RN1413SOT-23Digital transistor (NPN, resistors built in), 3 pins, ToshibaDigital transistor (NPN, resistors built in)3 pinsToshiba
    What it is
    Digital transistor (NPN, resistors built in)
    Maker
    Toshiba
    Package
    SOT-23
    Pins
    3
    Details
    Si-npn-Digi: Sw, 50V, 100mA, 400mW, R1=47k
    Source
    Published code list

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

  • RN2413SOT-23Digital transistor (PNP, resistors built in), 3 pins, ToshibaDigital transistor (PNP, resistors built in)3 pinsToshiba
    What it is
    Digital transistor (PNP, resistors built in)
    Maker
    Toshiba
    Package
    SOT-23
    Pins
    3
    Details
    Si-pnp-Digi: Sw, 50V, 100mA, 400mW, R1=47k
    Source
    Published code list

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

  • 8 more parts have no package on record. Nothing rules them out, so they stay.
    • HFCN-672+RF filter, Mini-CircuitsRF filterNot recordedMini-Circuits
      What it is
      RF filter
      Maker
      Mini-Circuits
      Package
      Not recorded
      Pins
      Not recorded
      Details
      LTCC filter, 6700-13000 MHz
      Source
      Manufacturer datasheet

      Is it dead? The meter test is below: This part.

    • SMAFJ16CATVS diode, Blue RocketTVS diodeNot recordedBlue Rocket
      What it is
      TVS diode
      Maker
      Blue Rocket
      Package
      Not recorded
      Pins
      Not recorded
      Source
      Manufacturer datasheet

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

    • SMAFJ16CA-MSTVS diode, MSKSEMITVS diodeNot recordedMSKSEMI
      What it is
      TVS diode
      Maker
      MSKSEMI
      Package
      Not recorded
      Pins
      Not recorded
      Source
      Manufacturer datasheet

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

    • SMAHFL16CATVS diode, Formosa MicrosemiTVS diodeNot recordedFormosa Microsemi
      What it is
      TVS diode
      Maker
      Formosa Microsemi
      Package
      Not recorded
      Pins
      Not recorded
      Source
      Manufacturer datasheet

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

    • SMF16CA-MFLTVS diode, Formosa MicrosemiTVS diodeNot recordedFormosa Microsemi
      What it is
      TVS diode
      Maker
      Formosa Microsemi
      Package
      Not recorded
      Pins
      Not recorded
      Source
      Manufacturer datasheet

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

    • 2SK40353 pins, RenesasNot recorded3 pinsRenesas
      What it is
      Not recorded
      Maker
      Renesas
      Package
      Not recorded
      Pins
      3
      Source
      Published code list

      Is it dead? The meter test is below: This part.

    • 12A01SPNP transistor, Sanyo ElectricPNP transistorNot recordedSanyo Electric
      What it is
      PNP transistor
      Maker
      Sanyo Electric
      Package
      Not recorded
      Pins
      Not recorded
      Details
      PNP transistor: AF, GP, 15V, 500mA, 200mW, B=300..700, 490MHz
      Source
      Published code list

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

    • 12A01SSPNP transistor, Sanyo ElectricPNP transistorNot recordedSanyo Electric
      What it is
      PNP transistor
      Maker
      Sanyo Electric
      Package
      Not recorded
      Pins
      Not recorded
      Details
      PNP transistor: AF, GP, 15V, 500mA, 200mW, B=300..700, 490MHz
      Source
      Published code list

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

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.

Digital transistor

Ohms range, part lifted. The datasheet gives the built-in resistors: R1 in series with the base, R2 from base to emitter.

Working, it reads

Base to emitter reads about R1 plus R2 either way round, about 20 kΩ on a 10 k and 10 k part, give or take their wide tolerance. Collector to emitter reads open. A part with no R2 reads a junction behind R1 one way instead.

Dead, it reads

  • Collector to emitter the same both ways, near 0 Ω with a continuous beep: shorted.
  • From the base, open or far above R1 plus R2: R1 has failed. Static damage shows here most often.
  • Base to emitter near 0 Ω: failed short.
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:
The readings depend on the resistor values, so an identical part elsewhere on the board is the surest reference. Measure it the same way.
Watch for:
On the diode range a good part with 10 kΩ resistors reads open on every pair, so a good part looks dead there. Use the ohms range.

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

This part

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.

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.

Silicon diode

Diode range, part lifted or one leg off the pad. Red probe on the anode.

Working, it reads

About 0.5 to 0.8 V anode to cathode, and open the other way. Small switching diodes read about 0.6 to 0.7 V; large rectifiers can read a little lower.

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: failed open.
  • A reading the wrong way round as well: 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 three-pin body can hold two diodes. With a common pin they read two junctions from that pin, just like a transistor; in series they read two drops end to end. Test each pair the datasheet names.

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

Digital transistor

Ohms range, part lifted. The datasheet gives the built-in resistors: R1 in series with the base, R2 from base to emitter.

Working, it reads

Base to emitter reads about R1 plus R2 either way round, about 20 kΩ on a 10 k and 10 k part, give or take their wide tolerance. Collector to emitter reads open. A part with no R2 reads a junction behind R1 one way instead.

Dead, it reads

  • Collector to emitter the same both ways, near 0 Ω with a continuous beep: shorted.
  • From the base, open or far above R1 plus R2: R1 has failed. Static damage shows here most often.
  • Base to emitter near 0 Ω: failed short.
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:
The readings depend on the resistor values, so an identical part elsewhere on the board is the surest reference. Measure it the same way.
Watch for:
On the diode range a good part with 10 kΩ resistors reads open on every pair, so a good part looks dead there. Use the ohms range.

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

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.

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.

Printed with a code easy to misread as XP

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

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