Skip to content

SMD code XY

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

  • GESD5V0X2B5SOD-523ESD protection diode, 2 pins, Galaxy MicroelectronicsESD protection diodeSOD-5232 pinsGalaxy Microelectronics
    What it is
    ESD protection diode
    Maker
    Galaxy Microelectronics
    Package
    SOD-523
    Pins
    2
    Details
    5V, 100W, Surface Mount TVS
    Source
    Manufacturer datasheet

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

  • GESD5V0X2BLSOD-882ESD protection diode, 2 pins, Galaxy MicroelectronicsESD protection diodeSOD-8822 pinsGalaxy Microelectronics
    What it is
    ESD protection diode
    Maker
    Galaxy Microelectronics
    Package
    SOD-882
    Pins
    2
    Details
    5V, 100W, Surface Mount TVS
    Source
    Manufacturer datasheet

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

  • GESD5V0X2BLP3DFN0603-2ESD protection diode, 2 pins, Galaxy MicroelectronicsESD protection diodeDFN0603-22 pinsGalaxy Microelectronics
    What it is
    ESD protection diode
    Maker
    Galaxy Microelectronics
    Package
    DFN0603-2
    Pins
    2
    Details
    5V, 150W, Surface Mount TVS
    Source
    Manufacturer datasheet

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

  • SMAJ24CSMATVS diode, 2 pins, DOWOTVS diodeSMA2 pinsDOWO
    What it is
    TVS diode
    Maker
    DOWO
    Package
    SMA
    Pins
    2
    Source
    Manufacturer datasheet

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

  • TGESD5V0X2B5SOD-523ESD protection diode, 2 pins, Galaxy MicroelectronicsESD protection diodeSOD-5232 pinsGalaxy Microelectronics
    What it is
    ESD protection diode
    Maker
    Galaxy Microelectronics
    Package
    SOD-523
    Pins
    2
    Details
    5V, 100W, Surface Mount TVS
    Source
    Manufacturer datasheet

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

  • TGESD5V0X2BLSOD-882ESD protection diode, 2 pins, Galaxy MicroelectronicsESD protection diodeSOD-8822 pinsGalaxy Microelectronics
    What it is
    ESD protection diode
    Maker
    Galaxy Microelectronics
    Package
    SOD-882
    Pins
    2
    Details
    5V, 100W, Surface Mount TVS
    Source
    Manufacturer datasheet

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

  • 2SB1714SOT-89PNP transistor, 3 pins, ROHMPNP transistorSOT-893 pinsROHM
    What it is
    PNP transistor
    Maker
    ROHM
    Package
    SOT-89
    Pins
    3
    Source
    Published code list

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

  • 2SD1851SOT-233 pins, Sanyo ElectricNot recordedSOT-233 pinsSanyo Electric
    What it is
    Not recorded
    Maker
    Sanyo Electric
    Package
    SOT-23
    Pins
    3
    Details
    Si-npn-Darl: AF-Drv, 80V, 200mA, 200mW, B>5000
    Source
    Published code list

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

  • 2SK209-YSOT-233 pins, ToshibaNot recordedSOT-233 pinsToshiba
    What it is
    Not recorded
    Maker
    Toshiba
    Package
    SOT-23
    Pins
    3
    Details
    FET n-type: GP, 50V, 10mA, 150mW, Idss=1.2..3mA
    Source
    Published code list

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

  • 2SK209YSOT-233 pins, ToshibaNot recordedSOT-233 pinsToshiba
    What it is
    Not recorded
    Maker
    Toshiba
    Package
    SOT-23
    Pins
    3
    Source
    Published code list

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

  • 2SK880-YSOT-3233 pins, ToshibaNot recordedSOT-3233 pinsToshiba
    What it is
    Not recorded
    Maker
    Toshiba
    Package
    SOT-323
    Pins
    3
    Details
    FET n-type: AF-Amp, 50V, 10mA, 100mW, Idss=1.2..3mA, Up<1.5V
    Source
    Published code list

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

  • 4 more parts have no package on record
    • MM5Z2V4BZener diode, Formosa MicrosemiZener diodeNot recordedNot recordedFormosa Microsemi
      What it is
      Zener diode
      Maker
      Formosa Microsemi
      Package
      Not recorded
      Pins
      Not recorded
      Source
      Manufacturer datasheet

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

    • MM5Z2V4B-Q1Zener diode, Formosa MicrosemiZener diodeNot recordedNot recordedFormosa Microsemi
      What it is
      Zener diode
      Maker
      Formosa Microsemi
      Package
      Not recorded
      Pins
      Not recorded
      Source
      Manufacturer datasheet

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

    • 74AUP1G125FW4Diodes IncorporatedNot recordedNot recordedNot recordedDiodes Incorporated
      What it is
      Not recorded
      Maker
      Diodes Incorporated
      Package
      Not recorded
      Pins
      Not recorded
      Details
      CMOS logic IC: Bus buffer gate with 3-state output
      Source
      Published code list

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

    • 74AUP1G125FZ4Diodes IncorporatedNot recordedNot recordedNot recordedDiodes Incorporated
      What it is
      Not recorded
      Maker
      Diodes Incorporated
      Package
      Not recorded
      Pins
      Not recorded
      Details
      CMOS logic IC: Bus buffer gate with 3-state output
      Source
      Published code list

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

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.

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.

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.

MOSFET

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

Working, it reads

One way between drain and source reads about 0.4 to 0.9 V, the body diode, and the other way open. The gate reads open to both other pins.

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.
  • No body diode at all: failed open.
On the board
the gate usually has a resistor to the source, which reads as that resistor and 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.

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.

Codes that begin with XY

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 30 more parts.

Did you find your part?

Open this in the search to correct a character or try another package.