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SMD code FQ in WSON

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

  • RT9032BGQWWSONLDO regulator, RichtekLDO regulatorRichtek
    What it is
    LDO regulator
    Maker
    Richtek
    Package
    WSON
    Pins
    Not recorded
    Details
    Linear voltage regulator IC: LDO, Prog. Dual Out, 1.2/2.8V..3.3/3.3V, 430mA, +CE1, +CE2
    Source
    Published code list

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

  • 10 more parts have no package on record. Nothing rules them out, so they stay.
    • L2SA1774QT1GPNP transistor, LRCPNP transistorLRC
      What it is
      PNP transistor
      Maker
      LRC
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Bipolar transistor, PNP, IC 150 mA, VCEO 50 V
      Source
      Manufacturer datasheet

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

    • S-L2SA1774QT1GPNP transistor, LRCPNP transistorLRC
      What it is
      PNP transistor
      Maker
      LRC
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Bipolar transistor, PNP, IC 150 mA, VCEO 50 V
      Source
      Manufacturer datasheet

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

    • TC8-1X+RF transformer, Mini-CircuitsRF transformerMini-Circuits
      What it is
      RF transformer
      Maker
      Mini-Circuits
      Package
      Not recorded
      Pins
      Not recorded
      Details
      RF transformer, 2-500 MHz
      Source
      Manufacturer datasheet

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

    • 2SA1576UBPNP transistor, ROHMPNP transistorROHM
      What it is
      PNP transistor
      Maker
      ROHM
      Package
      Not recorded
      Pins
      Not recorded
      Source
      Published code list

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

    • 2SA1774EBPNP transistor, ROHMPNP transistorROHM
      What it is
      PNP transistor
      Maker
      ROHM
      Package
      Not recorded
      Pins
      Not recorded
      Source
      Published code list

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

    • 2SA1774EBQROHMNot recordedROHM
      What it is
      Not recorded
      Maker
      ROHM
      Package
      Not recorded
      Pins
      3
      Details
      equivalent 2SA933ASQ
      Source
      Published code list

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

    • BD4934FVEVoltage supervisor, ROHMVoltage supervisorROHM
      What it is
      Voltage supervisor
      Maker
      ROHM
      Package
      Not recorded
      Pins
      Not recorded
      Details
      CMOS-IC: Voltage Detector 3,4V, Reset Push-pull output
      Source
      Published code list

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

    • BD4934GVoltage supervisor, ROHMVoltage supervisorROHM
      What it is
      Voltage supervisor
      Maker
      ROHM
      Package
      Not recorded
      Pins
      Not recorded
      Details
      CMOS-IC: Voltage Detector 3,4V, Reset Push-pull output
      Source
      Published code list

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

    • L2SA1774QT1PNP transistor, LRCPNP transistorLRC
      What it is
      PNP transistor
      Maker
      LRC
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Si-pnp: GP, 60V, 150mA, 150mW, B=120..270, 140MHz
      Source
      Published code list

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

    • MIC2211-1.5/3.1BMLLDO regulator, MicrelLDO regulatorMicrel
      What it is
      LDO regulator
      Maker
      Micrel
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Linear voltage regulator IC: LDO, Dual out, Vo1/Vo2=1.5V(150mA)/3.1V(300mA)±1%, +CE
      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.

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.

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.

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.

Printed with a code easy to misread as FQ

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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