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SMD code 3K in SOT-323

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

  • ABC858BW-HFSOT-323PNP transistor, 3 pins, ComchipPNP transistorSOT-3233 pinsComchip
    What it is
    PNP transistor
    Maker
    Comchip
    Package
    SOT-323
    Pins
    3
    Details
    -30 V, -0.1 A PNP transistor
    Source
    Manufacturer datasheet

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

  • BC858BWSOT-323Transistor, 3 pins, Formosa MicrosemiTransistorSOT-3233 pinsFormosa Microsemi
    What it is
    Transistor
    Maker
    Formosa Microsemi
    Package
    SOT-323
    Pins
    3
    Details
    SMD General Purpose PNP Transistors
    Source
    Manufacturer datasheet

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

  • BC858BW-HFSOT-323PNP transistor, 3 pins, ComchipPNP transistorSOT-3233 pinsComchip
    What it is
    PNP transistor
    Maker
    Comchip
    Package
    SOT-323
    Pins
    3
    Details
    -30 V, -0.1 A PNP transistor
    Source
    Manufacturer datasheet

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

  • BC858BW-Q1SOT-323PNP transistor, 3 pins, Formosa MicrosemiPNP transistorSOT-3233 pinsFormosa Microsemi
    What it is
    PNP transistor
    Maker
    Formosa Microsemi
    Package
    SOT-323
    Pins
    3
    Source
    Manufacturer datasheet

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

  • GSBC858BWSOT-323PNP transistor, 3 pins, Good-ArkPNP transistorSOT-3233 pinsGood-Ark
    What it is
    PNP transistor
    Maker
    Good-Ark
    Package
    SOT-323
    Pins
    3
    Details
    PNP transistor, 30 V, 0.1 A
    Source
    Manufacturer datasheet

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

  • LBC858BWT1GSOT-323PNP transistor, 3 pins, LRCPNP transistorSOT-3233 pinsLRC
    What it is
    PNP transistor
    Maker
    LRC
    Package
    SOT-323
    Pins
    3
    Details
    Bipolar transistor, PNP, IC 100 mA, VCEO 30 V
    Source
    Manufacturer datasheet

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

  • APX803L-41C3SOT-323Voltage supervisor, 3 pins, Diodes IncorporatedVoltage supervisorSOT-3233 pinsDiodes Incorporated
    What it is
    Voltage supervisor
    Maker
    Diodes Incorporated
    Package
    SOT-323
    Pins
    3
    Details
    Voltage detector IC: 4.1V±1.5%, -Reset ODO
    Source
    Published code list

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

  • BC858BWT1SOT-3233 pins, onsemiNot recordedSOT-3233 pinsonsemi
    What it is
    Not recorded
    Maker
    onsemi
    Package
    SOT-323
    Pins
    3
    Source
    Published code list

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

  • BC858BDWSOT-363Dual PNP transistor, 6 pins, Formosa MicrosemiDual PNP transistorSOT-3636 pinsFormosa Microsemi
    What it is
    Dual PNP transistor
    Maker
    Formosa Microsemi
    Package
    SOT-363
    Pins
    6
    Source
    Manufacturer datasheet

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

  • 6 more parts have no package on record. Nothing rules them out, so they stay.
    • ESD05B1ZESD protection diode, DiotecESD protection diodeNot recordedNot recordedDiotec
      What it is
      ESD protection diode
      Maker
      Diotec
      Package
      Not recorded
      Pins
      Not recorded
      Details
      ESD Protection Diodes in SMD
      Source
      Manufacturer datasheet

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

    • FPF2895VUCXLoad switch, onsemiLoad switchNot recordedNot recordedonsemi
      What it is
      Load switch
      Maker
      onsemi
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Current Limit Switch, with OVP and TRCB, 28 V / 5 A Rated
      Source
      Manufacturer datasheet

      Is it dead? The meter test is below: Load switch.

    • GSEZ5B250ESD protection diode, Good-ArkESD protection diodeNot recordedNot recordedGood-Ark
      What it is
      ESD protection diode
      Maker
      Good-Ark
      Package
      Not recorded
      Pins
      Not recorded
      Details
      ESD protection diode, VRWM 5 V
      Source
      Manufacturer datasheet

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

    • N05BT0603DESD protection diode, Formosa MicrosemiESD protection diodeNot recordedNot recordedFormosa Microsemi
      What it is
      ESD protection 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.

    • SGM2036S-0.9XXDH4GLDO regulator, 4 pins, SG MicroLDO regulatorNot recorded4 pinsSG Micro
      What it is
      LDO regulator
      Maker
      SG Micro
      Package
      Not recorded
      Pins
      4
      Details
      0.9 V output, 300mA, Low Power and Low Dropout RF Linear Regulator
      Source
      Manufacturer datasheet

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

    • VESD08D1-HD1ESD protection diode, VishayESD protection diodeNot recordedNot recordedVishay
      What it is
      ESD protection diode
      Maker
      Vishay
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Single-Line ESD-Protection Diode in DFN1006-2A
      Source
      Manufacturer datasheet

      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.

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.

Bipolar transistor

Diode range, part lifted or its base leg off the pad.

Working, it reads

From the base, one probe colour 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.

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.

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.

PNP transistor pair

Diode range, part lifted. Test each transistor on its own pins, as the datasheet's pinout gives them.

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.

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.

Load switch

Voltage, board powered, black probe on ground.

Working, it reads

Switched on, the output pin sits at the input voltage. Switched off, it sits near 0 V.

Dead, it reads

  • Output at the input voltage while switched off: the pass element has shorted.
  • Input present and switched on, no output: failed open, or shut down into a shorted load. Power off and measure output to ground.
On the board:
An output near 0 Ω to ground is usually the load. Lift the output pin to see which.
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 pinout and whether the enable is active high or low differ between parts. The datasheet gives both.

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.

Codes that begin with 3K

For a marking with its end worn or burnt off. Each code has a page of its own.

Codes not listed here are printed on 34 more parts.

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