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SMD code RF in SOT-523

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

  • MM5Z3V6TSOT-523Zener diode, 3 pins, SeCoSZener diode3 pinsSeCoS
    What it is
    Zener diode
    Maker
    SeCoS
    Package
    SOT-523
    Pins
    3
    Source
    Manufacturer datasheet

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

  • BFR181TSOT-523NPN transistor, 3 pins, InfineonNPN transistor3 pinsInfineon
    What it is
    NPN transistor
    Maker
    Infineon
    Package
    SOT-523
    Pins
    3
    Source
    Published code list

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

  • BZX84-C3V6TSOT-5233 pins, Diodes IncorporatedNot recorded3 pinsDiodes Incorporated
    What it is
    Not recorded
    Maker
    Diodes Incorporated
    Package
    SOT-523
    Pins
    3
    Details
    Z-diode: 3.6V±5%, 150mW
    Source
    Published code list

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

  • BZX84C3V6TSOT-523Zener diode, 3 pins, Diodes IncorporatedZener diode3 pinsDiodes Incorporated
    What it is
    Zener diode
    Maker
    Diodes Incorporated
    Package
    SOT-523
    Pins
    3
    Details
    zener 150mW 3.6V
    Source
    Published code list

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

  • CZRH3-55C3V6SOT-523Zener diode, 3 pins, ComchipZener diode3 pinsComchip
    What it is
    Zener diode
    Maker
    Comchip
    Package
    SOT-523
    Pins
    3
    Details
    Zener diode: 3.6..3.80V, Zzt=90, Izt=5mA, 150mW
    Source
    Published code list

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

  • 10 more parts have no package on record. Nothing rules them out, so they stay.
    • LFCN-120+RF filter, Mini-CircuitsRF filterNot recordedMini-Circuits
      What it is
      RF filter
      Maker
      Mini-Circuits
      Package
      Not recorded
      Pins
      Not recorded
      Details
      LTCC filter
      Source
      Manufacturer datasheet

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

    • NSR201MXSchottky diode, onsemiSchottky diodeNot recordedonsemi
      What it is
      Schottky diode
      Maker
      onsemi
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Schottky Barrier Diode for Mixer and Detector
      Source
      Manufacturer datasheet

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

    • NSVR201MXSchottky diode, onsemiSchottky diodeNot recordedonsemi
      What it is
      Schottky diode
      Maker
      onsemi
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Schottky Barrier Diode for Mixer and Detector
      Source
      Manufacturer datasheet

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

    • 2SC5336RF4 pins, RenesasNot recorded4 pinsRenesas
      What it is
      Not recorded
      Maker
      Renesas
      Package
      Not recorded
      Pins
      4
      Source
      Published code list

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

    • 74AXP1G14GMNXPNot recordedNot recordedNXP
      What it is
      Not recorded
      Maker
      NXP
      Package
      Not recorded
      Pins
      Not recorded
      Details
      CMOS logic IC: Inverter with Schmitt-trigger input
      Source
      Published code list

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

    • 74AXP1G14GNNXPNot recordedNot recordedNXP
      What it is
      Not recorded
      Maker
      NXP
      Package
      Not recorded
      Pins
      Not recorded
      Details
      CMOS logic IC: Inverter with Schmitt-trigger input
      Source
      Published code list

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

    • 74AXP1G14GSNXPNot recordedNot recordedNXP
      What it is
      Not recorded
      Maker
      NXP
      Package
      Not recorded
      Pins
      Not recorded
      Details
      CMOS logic IC: Inverter with Schmitt-trigger input
      Source
      Published code list

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

    • 74AXP1G14GXNXPNot recordedNot recordedNXP
      What it is
      Not recorded
      Maker
      NXP
      Package
      Not recorded
      Pins
      Not recorded
      Details
      CMOS logic IC: Inverter with Schmitt-trigger input
      Source
      Published code list

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

    • BD53E48G-MVoltage supervisor, ROHMVoltage supervisorNot recordedROHM
      What it is
      Voltage supervisor
      Maker
      ROHM
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Voltage detector IC: 4.8V±1%, -Reset PPO
      Source
      Published code list

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

    • BD5345FVEVoltage supervisor, ROHMVoltage supervisorNot recordedROHM
      What it is
      Voltage supervisor
      Maker
      ROHM
      Package
      Not recorded
      Pins
      Not recorded
      Details
      CMOS-IC: Voltage Detector 4,5V, Reset Push-pull output
      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.

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.

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.

Silicon diode

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

Working, it reads

About 0.5 to 0.8 V anode to cathode, and open the other way. Small switching diodes read about 0.6 to 0.7 V; large rectifiers can read a little lower.

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.
  • A reading the wrong way round as well: 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 three-pin body can hold two diodes. With a common pin they read two junctions from that pin, just like a transistor; in series they read two drops end to end. Test each pair the datasheet names.

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.

Schottky diode

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

Working, it reads

About 0.15 to 0.45 V anode to cathode, roughly half a silicon diode, 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.
  • A reading the wrong way round as well: leaky.
  • 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 large Schottky can read about 0.1 V forward and beep like a short, and leaks a little the wrong way when good, more when warm. It is shorted only if it reads the same both ways. Measure it cold, beside an identical cold one.

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.

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