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SMD code ZZ

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.

6 parts are printed ZZ

Not sure which one you have?

Answer up to 4 quick questions and these 6 parts are ranked, with a meter test that settles it. It works on a dead part too.

  • ESD9BL5V0PSOD-882ESD protection diode, 2 pins, Diotec
    What it is
    ESD protection diode
    Maker
    Diotec
    Package
    SOD-882
    Pins
    2
    Details
    ESD Protection Diodes in SMD
    Source
    From the manufacturer's datasheet

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

    Datasheetfor ESD9BL5V0P, opens in a new tab
  • ESD36VD5SOD-523ESD protection diode, 2 pins, JSCJ
    What it is
    ESD protection diode
    Maker
    JSCJ
    Package
    SOD-523
    Pins
    2
    Details
    ESD protection diode, VRWM 36 V
    Source
    From the manufacturer's datasheet

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

    Datasheetfor ESD36VD5, opens in a new tab
  • PESD5V0F1BLSOD-882ESD protection diode, 2 pins, Nexperia
    What it is
    ESD protection diode
    Maker
    Nexperia
    Package
    SOD-882
    Pins
    2
    Details
    Femtofarad bidirectional ESD protection diode
    Source
    From the manufacturer's datasheet

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

    Datasheetfor PESD5V0F1BL, opens in a new tab
  • PUMX1SOT-363NPN transistor, 6 pins, Nexperia
    What it is
    NPN transistor
    Maker
    Nexperia
    Package
    SOT-363
    Pins
    6
    Details
    40 V, 100 mA NPN/NPN general-purpose transistor
    Source
    From the manufacturer's datasheet

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

    Datasheetfor PUMX1, opens in a new tab
  • SMAJ100CASMATVS diode, 2 pins, Vishay
    What it is
    TVS diode
    Maker
    Vishay
    Package
    SMA
    Pins
    2
    Details
    400 W TVS diode, bidirectional
    Source
    From the manufacturer's datasheet

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

    Datasheetfor SMAJ100CA, opens in a new tab
  • 1 more part has no package on record
    • ESDSU5V0AE1ESD protection diode, JSCJ
      What it is
      ESD protection diode
      Maker
      JSCJ
      Package
      Not recorded
      Pins
      Not recorded
      Details
      ESD protection diode, VRWM 5 V
      Source
      From the manufacturer's datasheet

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

      Datasheetfor ESDSU5V0AE1, opens in a new tab

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.

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.

Printed with a code easy to misread as ZZ

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 ZZ

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 16 more parts.

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