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WhatSMDSign in

SMD code WSS

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.

5 parts are printed WSS

Not sure which one you have?

Answer up to 4 quick questions and these 5 parts are ranked, with a meter test that settles it. It works on a dead part too.

  • BCR169FTSFP-3Digital transistor (PNP, resistors built in), 3 pins, InfineonDigital transistor (PNP, resistors built in)TSFP-33 pinsInfineon
    What it is
    Digital transistor (PNP, resistors built in)
    Maker
    Infineon
    Package
    TSFP-3
    Pins
    3
    Details
    Si-pnp-Digi: Sw, 50V, 100mA, 250mW, R1=4.7k, 150MHz
    Source
    Published code list

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

  • BCR169TSOT-416Digital transistor (PNP, resistors built in), 3 pins, InfineonDigital transistor (PNP, resistors built in)SOT-4163 pinsInfineon
    What it is
    Digital transistor (PNP, resistors built in)
    Maker
    Infineon
    Package
    SOT-416
    Pins
    3
    Details
    Si-pnp-Digi: Sw, 50V, 100mA, 250mW, R1=4.7k, 150MHz
    Source
    Published code list

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

  • BCR169WSOT-323Digital transistor (PNP, resistors built in), 3 pinsDigital transistor (PNP, resistors built in)SOT-3233 pinsNot recorded
    What it is
    Digital transistor (PNP, resistors built in)
    Maker
    Not recorded
    Package
    SOT-323
    Pins
    3
    Details
    pnp dig 50V 0.1A 4k7
    Source
    Published code list

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

  • S-13A1B26-U5T1U3SOT-89-55 pins, ABLICNot recordedSOT-89-55 pinsABLIC
    What it is
    Not recorded
    Maker
    ABLIC
    Package
    SOT-89-5
    Pins
    5
    Details
    equivalent [2.6V LDO]
    Source
    Published code list

    Is it dead? The meter test is below: Voltage regulator.

  • 1 more part has no package on record
    • S-13A1B26-A6T1U36 pins, ABLICNot recordedNot recorded6 pinsABLIC
      What it is
      Not recorded
      Maker
      ABLIC
      Package
      Not recorded
      Pins
      6
      Details
      equivalent [2.6V LDO]
      Source
      Published code list

      Is it dead? The meter test is below: Voltage regulator.

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.

Digital transistor

Ohms range, part lifted. The datasheet gives the built-in resistors: R1 in series with the base, R2 from base to emitter.

Working, it reads

Base to emitter reads about R1 plus R2 either way round, about 20 kΩ on a 10 k and 10 k part, give or take their wide tolerance. Collector to emitter reads open. A part with no R2 reads a junction behind R1 one way instead.

Dead, it reads

  • Collector to emitter the same both ways, near 0 Ω with a continuous beep: shorted.
  • From the base, open or far above R1 plus R2: R1 has failed. Static damage shows here most often.
  • Base to emitter near 0 Ω: failed short.
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:
The readings depend on the resistor values, so an identical part elsewhere on the board is the surest reference. Measure it the same way.
Watch for:
On the diode range a good part with 10 kΩ resistors reads open on every pair, so a good part looks dead there. Use the ohms range.

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

Voltage regulator

Voltage, board powered, black probe on ground. Then ohms with the power off.

Working, it reads

Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

Dead, it reads

  • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
  • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
  • Power off, input to output near 0 Ω: shorted.
On the board:
An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
Compare:
The same regulator on another rail or another board shows the right voltages and the right resistances.
Watch for:
Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

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 WSS

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

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