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SMD code Y5y

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, y, is lower case, which on NXP and Philips parts is a date or factory code, so it was set aside and Y5 was searched.

88 parts are printed Y5y

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.

  • MMSZ5260BSOD-123FZener diode, 2 pins, DiotecZener diodeSOD-123F2 pinsDiotec
    What it is
    Zener diode
    Maker
    Diotec
    Package
    SOD-123F
    Pins
    2
    Source
    Manufacturer datasheet

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

  • PESDHC2FD15VUSOD-882ESD protection diode, 2 pins, PrisemiESD protection diodeSOD-8822 pinsPrisemi
    What it is
    ESD protection diode
    Maker
    Prisemi
    Package
    SOD-882
    Pins
    2
    Details
    ESD protection diode, 15 V working
    Source
    Manufacturer datasheet

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

  • S-LBZX84C16LT1GSOT-23Zener diode, 3 pins, LRCZener diodeSOT-233 pinsLRC
    What it is
    Zener diode
    Maker
    LRC
    Package
    SOT-23
    Pins
    3
    Details
    Zener diode, VZ Min 15.3 V, VZ Nom 16 V, VZ Max 17.1 V
    Source
    Manufacturer datasheet

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

  • SBZX584B43V-CSOD-523Zener diode, 2 pins, SeCoSZener diodeSOD-5232 pinsSeCoS
    What it is
    Zener diode
    Maker
    SeCoS
    Package
    SOD-523
    Pins
    2
    Source
    Manufacturer datasheet

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

  • SMV1273-079LFSOD-523Varicap diode, 2 pins, SkyworksVaricap diodeSOD-5232 pinsSkyworks
    What it is
    Varicap diode
    Maker
    Skyworks
    Package
    SOD-523
    Pins
    2
    Details
    SMV1273-079LF: Hyperabrupt Junction Tuning Varactor
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: PIN diode or varicap.

  • TBZX84C16SOT-23Zener diode, 3 pins, Galaxy MicroelectronicsZener diodeSOT-233 pinsGalaxy Microelectronics
    What it is
    Zener diode
    Maker
    Galaxy Microelectronics
    Package
    SOT-23
    Pins
    3
    Details
    16V, 350mW, Surface Mount Zener Diodes
    Source
    Manufacturer datasheet

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

  • TBZX584C16SOD-523Zener diode, 2 pins, Galaxy MicroelectronicsZener diodeSOD-5232 pinsGalaxy Microelectronics
    What it is
    Zener diode
    Maker
    Galaxy Microelectronics
    Package
    SOD-523
    Pins
    2
    Details
    16V, 150mW, Surface Mount Zener Diodes
    Source
    Manufacturer datasheet

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

  • ZGFM1011B-MSOD-123Zener diode, 2 pins, Formosa MicrosemiZener diodeSOD-1232 pinsFormosa Microsemi
    What it is
    Zener diode
    Maker
    Formosa Microsemi
    Package
    SOD-123
    Pins
    2
    Source
    Manufacturer datasheet

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

  • ACZRT55C16-GSOT-23Zener diode, 3 pins, ComchipZener diodeSOT-233 pinsComchip
    What it is
    Zener diode
    Maker
    Comchip
    Package
    SOT-23
    Pins
    3
    Details
    Zener diode: 15.3..17.1V, Izt=5.0mA, Zzt=40, 350mW
    Source
    Published code list

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

  • 6 more parts have no package on record
    • NC7WP08L8Logic gate, onsemiLogic gateNot recordedNot recordedonsemi
      What it is
      Logic gate
      Maker
      onsemi
      Package
      Not recorded
      Pins
      Not recorded
      Details
      TinyLogic ULP-A Dual 2-Input AND Gate
      Source
      Manufacturer datasheet

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

    • ZGFM1011B-MSZener 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.

    • ZGFM1011B-MS-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.

    • ZGFM1011B-MSTZener 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.

    • ZGFM1011B-MST-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.

    • 2SC5746RF transistor, NEC ElectronicsRF transistorNot recordedNot recordedNEC Electronics
      What it is
      RF transistor
      Maker
      NEC Electronics
      Package
      Not recorded
      Pins
      Not recorded
      Details
      NPN transistor: RF, HF, LN, 15V, 100mA, 140mW, B=100..145, 5.5GHz
      Source
      Published code list

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

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.

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.

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.

PIN diode or varicap

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

Working, it reads

About 0.6 to 0.9 V anode to cathode, and open the other way.

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.
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 varicap that has drifted in capacitance reads normal on a meter. Only a capacitance meter or the tuning itself shows it.

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

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.

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