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SMD code XBs

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.

The last letter, s, is lower case, which on NXP and Philips parts is a date or factory code, so it was set aside and XB was searched.

74 parts are printed XBs

Not sure which one you have?

Answer up to 4 quick questions and these 50 parts are ranked, with a meter test that settles it. It works on a dead part too.

  • 5LP01M-TLSOT-3233 pins, onsemiNot recordedSOT-3233 pinsonsemi
    What it is
    Not recorded
    Maker
    onsemi
    Package
    SOT-323
    Pins
    3
    Source
    Published code list

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

  • APX810-44SASOT-23Voltage supervisor, 3 pins, Diodes IncorporatedVoltage supervisorSOT-233 pinsDiodes Incorporated
    What it is
    Voltage supervisor
    Maker
    Diodes Incorporated
    Package
    SOT-23
    Pins
    3
    Details
    Voltage detector IC: 4.38V±1.5%, +Reset PPO
    Source
    Published code list

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

  • APX810S-44SA-7SOT-23Voltage supervisor, 3 pins, Diodes IncorporatedVoltage supervisorSOT-233 pinsDiodes Incorporated
    What it is
    Voltage supervisor
    Maker
    Diodes Incorporated
    Package
    SOT-23
    Pins
    3
    Details
    Voltage detector IC: 4.38V±1.5%, +Reset PPO, Rdt=240ms
    Source
    Published code list

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

  • BSD840NSOT-3636 pins, InfineonNot recordedSOT-3636 pinsInfineon
    What it is
    Not recorded
    Maker
    Infineon
    Package
    SOT-363
    Pins
    6
    Source
    Published code list

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

  • BZX99-C5V1SOT-233 pins, NexperiaNot recordedSOT-233 pinsNexperia
    What it is
    Not recorded
    Maker
    Nexperia
    Package
    SOT-23
    Pins
    3
    Details
    5.1V 0.3W zener
    Source
    Published code list

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

  • BZX284-B8V2MicroMELF2 pins, NexperiaNot recordedMicroMELF2 pinsNexperia
    What it is
    Not recorded
    Maker
    Nexperia
    Package
    MicroMELF
    Pins
    2
    Details
    0.4W zener 8.2V E24 ±2%
    Source
    Published code list

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

  • BZX784C10SOD-723Zener diode, 2 pins, PanjitZener diodeSOD-7232 pinsPanjit
    What it is
    Zener diode
    Maker
    Panjit
    Package
    SOD-723
    Pins
    2
    Source
    Published code list

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

  • CMDZ5231BSOD-323Zener diode, 2 pins, Central SemiconductorZener diodeSOD-3232 pinsCentral Semiconductor
    What it is
    Zener diode
    Maker
    Central Semiconductor
    Package
    SOD-323
    Pins
    2
    Details
    250mW zener 5% 5.1V
    Source
    Published code list

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

  • KTB1124-BSOT-89PNP transistor, 3 pins, KECPNP transistorSOT-893 pinsKEC
    What it is
    PNP transistor
    Maker
    KEC
    Package
    SOT-89
    Pins
    3
    Details
    PNP transistor: GP, 60V, 3A, 1W, B=140..280, 150MHz
    Source
    Published code list

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

  • PZU2.7B2ASOD-323Zener diode, 2 pins, NXPZener diodeSOD-3232 pinsNXP
    What it is
    Zener diode
    Maker
    NXP
    Package
    SOD-323
    Pins
    2
    Source
    Published code list

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

  • 5 more parts have no package on record
    • 5LP01SSanyo ElectricNot recordedNot recordedNot recordedSanyo Electric
      What it is
      Not recorded
      Maker
      Sanyo Electric
      Package
      Not recorded
      Pins
      Not recorded
      Details
      p-MOS*+Di: Sw, U-Hi-Sp, 50V, 70mA, 150mW, 20/250ns
      Source
      Published code list

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

    • 5LP01SSSanyo ElectricNot recordedNot recordedNot recordedSanyo Electric
      What it is
      Not recorded
      Maker
      Sanyo Electric
      Package
      Not recorded
      Pins
      Not recorded
      Details
      p-MOS*+Di: Sw, U-Hi-Sp, 50V, 70mA, 150mW, 20/250ns
      Source
      Published code list

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

    • 74AUP1G02FX4Diodes IncorporatedNot recordedNot recordedNot recordedDiodes Incorporated
      What it is
      Not recorded
      Maker
      Diodes Incorporated
      Package
      Not recorded
      Pins
      Not recorded
      Details
      CMOS logic IC: 2-input NOR gate
      Source
      Published code list

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

    • BD46312GVoltage supervisor, ROHMVoltage supervisorNot recordedNot recordedROHM
      What it is
      Voltage supervisor
      Maker
      ROHM
      Package
      Not recorded
      Pins
      Not recorded
      Details
      CMOS-IC: Voltage Detector 3,1V, -Reset Push-pull output, 200ms
      Source
      Published code list

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

    • KDZ15BZener diode, ROHMZener diodeNot recordedNot recordedROHM
      What it is
      Zener diode
      Maker
      ROHM
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Z-diode: 15V±2,5%, 20mA, 1W
      Source
      Published code list

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

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.

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.

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.

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.

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