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SMD code ST-

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.

62 parts are printed ST-

Not sure which one you have?

Answer up to 4 quick questions and these 50 parts are ranked, with a meter test that settles it. It works on a dead part too.

  • PMF180ASOD-123FTVS diode, 2 pins, StarHopeTVS diodeSOD-123F2 pinsStarHope
    What it is
    TVS diode
    Maker
    StarHope
    Package
    SOD-123F
    Pins
    2
    Details
    Transient voltage supressor: Vbr=200..220V, Vrwm=180V, Ipp=0.69A, 200W(1ms)
    Source
    Published code list

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

  • R1122N371BSOT-23-55 pins, Nisshinbo Micro DevicesNot recordedSOT-23-55 pinsNisshinbo Micro Devices
    What it is
    Not recorded
    Maker
    Nisshinbo Micro Devices
    Package
    SOT-23-5
    Pins
    5
    Details
    VR-IC: LDO, LN, CE, 3,7V±2%, 150mA
    Source
    Published code list

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

  • R3116L481CDFNVoltage supervisor, RicohVoltage supervisorDFNNot recordedRicoh
    What it is
    Voltage supervisor
    Maker
    Ricoh
    Package
    DFN
    Pins
    Not recorded
    Details
    Voltage detector IC: 4.8V±0.8%, -Reset PPO
    Source
    Published code list

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

  • R3160N480BSOT-23-6Voltage supervisor, 6 pins, RicohVoltage supervisorSOT-23-66 pinsRicoh
    What it is
    Voltage supervisor
    Maker
    Ricoh
    Package
    SOT-23-6
    Pins
    6
    Details
    Voltage detector IC: 48.0V±1.5%, +Reset ODO
    Source
    Published code list

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

  • RP152L018BDFNLDO regulator, RicohLDO regulatorDFNNot recordedRicoh
    What it is
    LDO regulator
    Maker
    Ricoh
    Package
    DFN
    Pins
    Not recorded
    Details
    Linear voltage regulator IC: LDO, Dual out, Vout1/Vout2=1.8V/1.8V±1%, 150mA, +CE, CL
    Source
    Published code list

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

  • SMAJ180AGSMATVS diode, 2 pins, First SemiconductorTVS diodeSMA2 pinsFirst Semiconductor
    What it is
    TVS diode
    Maker
    First Semiconductor
    Package
    SMA
    Pins
    2
    Details
    Transient voltage supressor: Vrwm=180V, Vbr=200..230.4V, Ipp=1.4A, 400W(1ms)
    Source
    Published code list

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

  • SMAJ188SMATVS diode, 2 pins, VishayTVS diodeSMA2 pinsVishay
    What it is
    TVS diode
    Maker
    Vishay
    Package
    SMA
    Pins
    2
    Details
    TVS: 209..255V, 0.90A, 400W(1ms)
    Source
    Published code list

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

  • SMAJ188ASMATVS diode, 2 pins, Taiwan SemiconductorTVS diodeSMA2 pinsTaiwan Semiconductor
    What it is
    TVS diode
    Maker
    Taiwan Semiconductor
    Package
    SMA
    Pins
    2
    Details
    188V, 400W, Surface Mount TVS
    Source
    Published code list

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

  • SMAJ200ASMATVS diode, 2 pins, Diodes IncorporatedTVS diodeSMA2 pinsDiodes Incorporated
    What it is
    TVS diode
    Maker
    Diodes Incorporated
    Package
    SMA
    Pins
    2
    Source
    Published code list

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

  • TV04A181J-GSMATVS diode, 2 pins, ComchipTVS diodeSMA2 pinsComchip
    What it is
    TVS diode
    Maker
    Comchip
    Package
    SMA
    Pins
    2
    Details
    Transient voltage supressor: Vrwm=180.0V, Vbr=200.0..220.0V, Ipp=1.37A, 400W(1ms)
    Source
    Published code list

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

  • 5 more parts have no package on record
    • SMAS180ATVS diode, Formosa MicrosemiTVS diodeNot recordedNot recordedFormosa Microsemi
      What it is
      TVS diode
      Maker
      Formosa Microsemi
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Transient voltage supressor: Vrwm=180V, Vbr=201..222V, Ipp=1.4A, 400W(1ms)
      Source
      Published code list

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

    • SMF4L200AQTVS diode, Diodes IncorporatedTVS diodeNot recordedNot recordedDiodes Incorporated
      What it is
      TVS diode
      Maker
      Diodes Incorporated
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Transient voltage supressor: Vrwm=200V, Vbr=224..248V, Ipp=1.2A, 400W(1ms)
      Source
      Published code list

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

    • XC6127C44GNRVoltage supervisor, TorexVoltage supervisorNot recordedNot recordedTorex
      What it is
      Voltage supervisor
      Maker
      Torex
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Voltage detector IC: 4.4V±0.8%, +Reset PPO, -MR, Rdt=100ms
      Source
      Published code list

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

    • XC6223C34BNR-GLDO regulator, TorexLDO regulatorNot recordedNot recordedTorex
      What it is
      LDO regulator
      Maker
      Torex
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Linear voltage regulator IC: LDO, 3.45V±1%, 300mA, +CE, PDR
      Source
      Published code list

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

    • XC6237B291NR-GLDO regulator, TorexLDO regulatorNot recordedNot recordedTorex
      What it is
      LDO regulator
      Maker
      Torex
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Linear voltage regulator IC: LDO, 2.9V±1%, 150mA, +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.

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.

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.

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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