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SMD code FZ in SOT-23

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

  • 2SD2657KSOT-23NPN transistor, ROHMNPN transistorROHM
    What it is
    NPN transistor
    Maker
    ROHM
    Package
    SOT-23
    Pins
    3
    Source
    Published code list

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

  • BSV65RBSOT-23InfineonNot recordedInfineon
    What it is
    Not recorded
    Maker
    Infineon
    Package
    SOT-23
    Pins
    3
    Source
    Published code list

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

  • RT9819C-44PVSOT-23Voltage supervisor, RichtekVoltage supervisorRichtek
    What it is
    Voltage supervisor
    Maker
    Richtek
    Package
    SOT-23
    Pins
    3
    Details
    Voltage Detector
    Source
    Published code list

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

  • SiP810CSEUDTSOT-23Voltage supervisor, VishayVoltage supervisorVishay
    What it is
    Voltage supervisor
    Maker
    Vishay
    Package
    SOT-23
    Pins
    3
    Details
    CMOS-IC: Voltage Detectorr2,93V, Reset Push-pull output 210ms
    Source
    Published code list

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

  • TC1073-2.8VCH713SOT-23LDO regulator, MicrochipLDO regulatorMicrochip
    What it is
    LDO regulator
    Maker
    Microchip
    Package
    SOT-23
    Pins
    3
    Source
    Published code list

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

  • UN2225SOT-23PanNot recordedPan
    What it is
    Not recorded
    Maker
    Pan
    Package
    SOT-23
    Pins
    3
    Details
    Si-npn-Digi: Sw, 50V, 500mA, 200mW, 250MHz, R1=10k
    Source
    Published code list

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

  • UNR2225SOT-23PanNot recordedPan
    What it is
    Not recorded
    Maker
    Pan
    Package
    SOT-23
    Pins
    3
    Details
    Si-npn-Digi: Sw, 50V, 500mA, 200mW, 250MHz, R1=10k
    Source
    Published code list

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

  • 8 more parts have no package on record. Nothing rules them out, so they stay.
    • MM3Z10VBW-CZener diode, SeCoSZener diodeSeCoS
      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.

    • MM5Z3V9BZener diode, Formosa MicrosemiZener diodeFormosa 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.

    • MM5Z3V9B-Q1Zener diode, Formosa MicrosemiZener diodeFormosa 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.

    • 1P2GU04QDRYTexas InstrumentsNot recordedTexas Instruments
      What it is
      Not recorded
      Maker
      Texas Instruments
      Package
      Not recorded
      Pins
      Not recorded
      Details
      CMOS logic IC: Dual unbuffered inverter
      Source
      Published code list

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

    • 2SD2701ROHMNot recordedROHM
      What it is
      Not recorded
      Maker
      ROHM
      Package
      Not recorded
      Pins
      3
      Source
      Published code list

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

    • FP6121-BVSPLDO regulator, FitipowerLDO regulatorFitipower
      What it is
      LDO regulator
      Maker
      Fitipower
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Linear voltage regulator IC: LDO, Dual out, Vout1/Vout2=3.3V/2.5V±2%, 150mA, +CE
      Source
      Published code list

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

    • IXD5127C54ANRVoltage supervisor, IXYSVoltage supervisorIXYS
      What it is
      Voltage supervisor
      Maker
      IXYS
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Voltage detector IC: 5.4V±0.8%, -Reset PPO, -MR, 50ms Rt delay
      Source
      Published code list

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

    • IXD5127N54FNRVoltage supervisor, IXYSVoltage supervisorIXYS
      What it is
      Voltage supervisor
      Maker
      IXYS
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Voltage detector IC: 5.4V±0.8%, +Reset ODO, -MR, 50ms Rt delay
      Source
      Published code list

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

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.

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.

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.

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.

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.

Printed with a code easy to misread as FZ

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 1 more part.

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