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SMD code 3Lp 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.

The last letter, p, is lower case, which on NXP and Philips parts is a date or factory code, so it was set aside and 3L was searched.

14 parts in SOT-23 are printed 3Lp

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.

  • ABC858C-HFSOT-23PNP transistor, ComchipPNP transistorSOT-23Comchip
    What it is
    PNP transistor
    Maker
    Comchip
    Package
    SOT-23
    Pins
    3
    Details
    -30 V, -0.1 A PNP transistor
    Source
    Manufacturer datasheet

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

  • BC858CSOT-23PNP transistor, InfineonPNP transistorSOT-23Infineon
    What it is
    PNP transistor
    Maker
    Infineon
    Package
    SOT-23
    Pins
    3
    Details
    -30 V PNP small-signal transistor, gain group C
    Source
    Manufacturer datasheet

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

  • BC858C-CSOT-23Transistor, SeCoSTransistorSOT-23SeCoS
    What it is
    Transistor
    Maker
    SeCoS
    Package
    SOT-23
    Pins
    3
    Details
    Bipolar transistor
    Source
    Manufacturer datasheet

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

  • BC858C-HFSOT-23PNP transistor, ComchipPNP transistorSOT-23Comchip
    What it is
    PNP transistor
    Maker
    Comchip
    Package
    SOT-23
    Pins
    3
    Details
    -30 V, -0.1 A PNP transistor
    Source
    Manufacturer datasheet

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

  • BC858CLSOT-23PNP transistor, onsemiPNP transistorSOT-23onsemi
    What it is
    PNP transistor
    Maker
    onsemi
    Package
    SOT-23
    Pins
    3
    Details
    General Purpose Transistors Series
    Source
    Manufacturer datasheet

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

  • BC858CQSOT-23PNP transistor, Yangjie Electronic TechPNP transistorSOT-23Yangjie Electronic Tech
    What it is
    PNP transistor
    Maker
    Yangjie Electronic Tech
    Package
    SOT-23
    Pins
    3
    Source
    Manufacturer datasheet

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

  • LBC858CLT1GSOT-23PNP transistor, LRCPNP transistorSOT-23LRC
    What it is
    PNP transistor
    Maker
    LRC
    Package
    SOT-23
    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.

  • S-LBC858CLT1GSOT-23PNP transistor, LRCPNP transistorSOT-23LRC
    What it is
    PNP transistor
    Maker
    LRC
    Package
    SOT-23
    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.

  • TBC858CSOT-23PNP transistor, Galaxy MicroelectronicsPNP transistorSOT-23Galaxy Microelectronics
    What it is
    PNP transistor
    Maker
    Galaxy Microelectronics
    Package
    SOT-23
    Pins
    3
    Details
    30V, 0.1A, General Purpose PNP Bipolar Transistor
    Source
    Manufacturer datasheet

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

  • 2SK608-PSOT-23PanasonicNot recordedSOT-23Panasonic
    What it is
    Not recorded
    Maker
    Panasonic
    Package
    SOT-23
    Pins
    3
    Details
    FET n-type: FM-Tun, 30V, 20mA, 20mW, Idss=0.5..5mA, Up<3V
    Source
    Published code list

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

  • GM858CSOT-23PNP transistor, Guilin Strong Micro ElectronicsPNP transistorSOT-23Guilin Strong Micro Electronics
    What it is
    PNP transistor
    Maker
    Guilin Strong Micro Electronics
    Package
    SOT-23
    Pins
    3
    Details
    PNP transistor: GP, 30V, 100mA, 310mW, B=420..800, >150MHz
    Source
    Published code list

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

  • HABC858CSOT-23PNP transistor, Hottech ElectronicsPNP transistorSOT-23Hottech Electronics
    What it is
    PNP transistor
    Maker
    Hottech Electronics
    Package
    SOT-23
    Pins
    3
    Details
    PNP transistor: GP, 30V, 100mA, 200mW, >100MHz, B=420..800
    Source
    Published code list

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

  • R3131N29AC3SOT-23Nisshinbo Micro DevicesNot recordedSOT-23Nisshinbo Micro Devices
    What it is
    Not recorded
    Maker
    Nisshinbo Micro Devices
    Package
    SOT-23
    Pins
    3
    Details
    CMOS-IC: Voltage Detector 2,9V, Reset Open drain output, 50ms
    Source
    Published code list

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

  • BC858CWSOT-323Transistor, Formosa MicrosemiTransistorSOT-323Formosa 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.

  • 1 more part has no package on record. Nothing rules it out, so it stays.
    • FM3L45-MHTSchottky diode, Formosa MicrosemiSchottky diodeNot recordedFormosa Microsemi
      What it is
      Schottky diode
      Maker
      Formosa Microsemi
      Package
      Not recorded
      Pins
      Not recorded
      Source
      Manufacturer datasheet

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

MOSFET

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

Working, it reads

One way between drain and source reads about 0.4 to 0.9 V, the body diode, and the other way open. The gate reads open to both other pins.

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.
  • No body diode at all: failed open.
On the board
the gate usually has a resistor to the source, which reads as that resistor and 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.

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.

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.

Printed with a code easy to misread as 3Lp

One character differs, and it is one that is easy to confuse under a lamp. Each code has a page of its own.

Did you find your part?

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