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SMD code ZD-

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.

67 parts are printed ZD-

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.

  • BZT52C8V2S-FLSOD-323Zener diode, 2 pins, Formosa MicrosemiZener diodeSOD-3232 pinsFormosa Microsemi
    What it is
    Zener diode
    Maker
    Formosa Microsemi
    Package
    SOD-323
    Pins
    2
    Source
    Manufacturer datasheet

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

  • BZT52C8V2S-FL-Q1SOD-323Zener diode, 2 pins, Formosa MicrosemiZener diodeSOD-3232 pinsFormosa Microsemi
    What it is
    Zener diode
    Maker
    Formosa Microsemi
    Package
    SOD-323
    Pins
    2
    Source
    Manufacturer datasheet

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

  • ESD2V5-CSOD-523ESD protection diode, 2 pins, SeCoSESD protection diodeSOD-5232 pinsSeCoS
    What it is
    ESD protection diode
    Maker
    SeCoS
    Package
    SOD-523
    Pins
    2
    Source
    Manufacturer datasheet

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

  • ESD5Z2.5SOD-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
    2.5V, 120W, Surface Mount TVS
    Source
    Manufacturer datasheet

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

  • F2SA5350ASOT-23PNP transistor, 3 pins, Formosa MicrosemiPNP transistorSOT-233 pinsFormosa Microsemi
    What it is
    PNP transistor
    Maker
    Formosa Microsemi
    Package
    SOT-23
    Pins
    3
    Source
    Manufacturer datasheet

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

  • MM3Z8V2CSOD-323Zener diode, 2 pins, onsemiZener diodeSOD-3232 pinsonsemi
    What it is
    Zener diode
    Maker
    onsemi
    Package
    SOD-323
    Pins
    2
    Details
    Zener diode, 7.5 V, 0.005 A
    Source
    Manufacturer datasheet

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

  • MMSZ4713SOD-123Zener diode, 2 pins, VishayZener diodeSOD-1232 pinsVishay
    What it is
    Zener diode
    Maker
    Vishay
    Package
    SOD-123
    Pins
    2
    Source
    Manufacturer datasheet

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

  • MMSZ4713-GSOD-123Zener diode, 2 pins, VishayZener diodeSOD-1232 pinsVishay
    What it is
    Zener diode
    Maker
    Vishay
    Package
    SOD-123
    Pins
    2
    Details
    30 V Zener diode
    Source
    Manufacturer datasheet

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

  • PBSS5350TSOT-23PNP transistor, 3 pins, YFWPNP transistorSOT-233 pinsYFW
    What it is
    PNP transistor
    Maker
    YFW
    Package
    SOT-23
    Pins
    3
    Details
    PNP bipolar transistor
    Source
    Manufacturer datasheet

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

  • PDZ8.2BSOD-323Zener diode, 2 pins, Galaxy MicroelectronicsZener diodeSOD-3232 pinsGalaxy Microelectronics
    What it is
    Zener diode
    Maker
    Galaxy Microelectronics
    Package
    SOD-323
    Pins
    2
    Details
    8.2V, 400mW, Surface Mount Zener Diodes
    Source
    Manufacturer datasheet

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

  • 5 more parts have no package on record
    • BFU730LXRF transistor, 3 pins, NXPRF transistorNot recorded3 pinsNXP
      What it is
      RF transistor
      Maker
      NXP
      Package
      Not recorded
      Pins
      3
      Details
      NPN wideband silicon germanium RF transistor
      Source
      Manufacturer datasheet

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

    • CURN101-HFRectifier, ComchipRectifierNot recordedNot recordedComchip
      What it is
      Rectifier
      Maker
      Comchip
      Package
      Not recorded
      Pins
      Not recorded
      Details
      200 V, 1 A rectifier
      Source
      Manufacturer datasheet

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

    • ESD5Z2.5T1GESD protection diode, UMWESD protection diodeNot recordedNot recordedUMW
      What it is
      ESD protection diode
      Maker
      UMW
      Package
      Not recorded
      Pins
      Not recorded
      Source
      Manufacturer datasheet

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

    • MM3Z8V2CW-CZener diode, SeCoSZener diodeNot recordedNot recordedSeCoS
      What it is
      Zener diode
      Maker
      SeCoS
      Package
      Not recorded
      Pins
      Not recorded
      Source
      Manufacturer datasheet

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

    • NCP360MULoad switch, onsemiLoad switchNot recordedNot recordedonsemi
      What it is
      Load switch
      Maker
      onsemi
      Package
      Not recorded
      Pins
      Not recorded
      Details
      USB Positive Overvoltage Protection Controller with Internal PMOS FET and Status FLAG
      Source
      Manufacturer datasheet

      Is it dead? The meter test is below: Load switch.

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.

Bipolar transistor

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

Working, it reads

From the base, one probe colour 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.

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.

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.

Load switch

Voltage, board powered, black probe on ground.

Working, it reads

Switched on, the output pin sits at the input voltage. Switched off, it sits near 0 V.

Dead, it reads

  • Output at the input voltage while switched off: the pass element has shorted.
  • Input present and switched on, no output: failed open, or shut down into a shorted load. Power off and measure output to ground.
On the board:
An output near 0 Ω to ground is usually the load. Lift the output pin to see which.
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 pinout and whether the enable is active high or low differ between parts. The datasheet gives both.

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 ZD-

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

Codes not listed here are printed on 53 more parts.

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