Skip to content

SMD code RX in SOT-723

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

  • RZM001P02SOT-723P-channel MOSFET, ROHMP-channel MOSFETROHM
    What it is
    P-channel MOSFET
    Maker
    ROHM
    Package
    SOT-723
    Pins
    3
    Details
    Pch -20V -100mA Small Signal MOSFET
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: P-channel MOSFET.

  • 14 more parts have no package on record. Nothing rules them out, so they stay.
    • LFCN-630D+RF filter, Mini-CircuitsRF filterMini-Circuits
      What it is
      RF filter
      Maker
      Mini-Circuits
      Package
      Not recorded
      Pins
      Not recorded
      Details
      LTCC filter, DC-630 MHz
      Source
      Manufacturer datasheet

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

    • SMAFJ9.0A-MSTVS diode, MSKSEMITVS diodeMSKSEMI
      What it is
      TVS diode
      Maker
      MSKSEMI
      Package
      Not recorded
      Pins
      Not recorded
      Source
      Manufacturer datasheet

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

    • SMAFJ90ATVS diode, Blue RocketTVS diodeBlue Rocket
      What it is
      TVS diode
      Maker
      Blue Rocket
      Package
      Not recorded
      Pins
      Not recorded
      Source
      Manufacturer datasheet

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

    • SMAHFL90ATVS diode, Formosa MicrosemiTVS diodeFormosa Microsemi
      What it is
      TVS diode
      Maker
      Formosa Microsemi
      Package
      Not recorded
      Pins
      Not recorded
      Source
      Manufacturer datasheet

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

    • SMASF90ATVS diode, Formosa MicrosemiTVS diodeFormosa Microsemi
      What it is
      TVS diode
      Maker
      Formosa Microsemi
      Package
      Not recorded
      Pins
      Not recorded
      Source
      Manufacturer datasheet

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

    • SMASF90A-Q1TVS diode, Formosa MicrosemiTVS diodeFormosa Microsemi
      What it is
      TVS diode
      Maker
      Formosa Microsemi
      Package
      Not recorded
      Pins
      Not recorded
      Source
      Manufacturer datasheet

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

    • SMF90A-MFLTVS diode, Formosa MicrosemiTVS diodeFormosa Microsemi
      What it is
      TVS diode
      Maker
      Formosa Microsemi
      Package
      Not recorded
      Pins
      Not recorded
      Source
      Manufacturer datasheet

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

    • 1SMA22ATVS diode, onsemiTVS diodeonsemi
      What it is
      TVS diode
      Maker
      onsemi
      Package
      Not recorded
      Pins
      Not recorded
      Details
      TVS: 22V±5%, 11.3A, 400W (1ms)
      Source
      Published code list

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

    • 1SMA22CATVS diode, onsemiTVS diodeonsemi
      What it is
      TVS diode
      Maker
      onsemi
      Package
      Not recorded
      Pins
      Not recorded
      Details
      TVS: 22V±5%, 11.3A, 400W (1ms), Bidirectional
      Source
      Published code list

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

    • IXD5127C50FNRVoltage supervisor, IXYSVoltage supervisorIXYS
      What it is
      Voltage supervisor
      Maker
      IXYS
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Voltage detector IC: 5.0V±0.8%, +Reset PPO, -MR, 50ms Rt delay
      Source
      Published code list

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

    • KTC3770UNPN transistor, KECNPN transistorKEC
      What it is
      NPN transistor
      Maker
      KEC
      Package
      Not recorded
      Pins
      Not recorded
      Source
      An older or alternative marking, from a published code list

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

    • KTC3770VKECNot recordedKEC
      What it is
      Not recorded
      Maker
      KEC
      Package
      Not recorded
      Pins
      Not recorded
      Details
      npn 20V 0.1A Ft 5GHz min.
      Source
      Published code list

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

    • LT4ME90ATVS diode, Lite-On SemiconductorTVS diodeLite-On Semiconductor
      What it is
      TVS diode
      Maker
      Lite-On Semiconductor
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Transient voltage supressor: Vrwm=90V, Vbr=100..111V, Ipp=2.7A, 400W(1ms)
      Source
      Published code list

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

    • P2SMSJ90ATVS diode, YeashinTVS diodeYeashin
      What it is
      TVS diode
      Maker
      Yeashin
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Transient voltage supressor: Vrwm=90V, Vbr=100..111V, Ipp=1.2A, 200W(1ms)
      Source
      Published code list

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

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.

P-channel MOSFET

Diode range, part lifted. Test drain to source first, then short gate to source and test again.

Working, it reads

Red probe on the drain, black on the source: about 0.4 to 0.9 V, the body diode. Open the other way. The gate reads open to both other pins, both ways.

Dead, it reads

  • Drain to source the same both ways, near 0 V with a continuous beep, and still so after shorting gate to source: shorted. The classic failure.
  • The gate reads low to source or drain: gate shorted. Often all three pins end up shorted together.
  • No body diode at all: failed open.
On the board
the gate usually has a resistor to the source, so gate to source reads that resistor, which is not a fault. Lift a leg to be sure.
Compare:
If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.
Watch for:
The diode range can charge the gate enough to turn the part on, and then drain to source reads near 0 both ways on a good part. Short gate to source and test again before you condemn it.

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.

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.

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.

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.

Did you find your part?

Open this in the search to correct a character or try another package.