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SMD code K3p

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 K3 was searched.

121 parts are printed K3p

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.

  • LDTB114TLT1GSOT-23Digital transistor (PNP, resistors built in), 3 pins, LRCDigital transistor (PNP, resistors built in)SOT-233 pinsLRC
    What it is
    Digital transistor (PNP, resistors built in)
    Maker
    LRC
    Package
    SOT-23
    Pins
    3
    Details
    Digital transistor (bias resistors built in), PNP, IC 500 mA, VCEO 40 V
    Source
    Manufacturer datasheet

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

  • LMSZ5253BT1GSOD-123Zener diode, 2 pins, LRCZener diodeSOD-1232 pinsLRC
    What it is
    Zener diode
    Maker
    LRC
    Package
    SOD-123
    Pins
    2
    Details
    Zener diode, VZ Min 23.75 V, VZ Nom 25 V, VZ Max 26.25 V
    Source
    Manufacturer datasheet

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

  • MMBZ5253ASOT-23Zener diode, 3 pins, PanjitZener diodeSOT-233 pinsPanjit
    What it is
    Zener diode
    Maker
    Panjit
    Package
    SOT-23
    Pins
    3
    Source
    Manufacturer datasheet

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

  • MMBZ5253A-HFSOT-23Zener diode, 3 pins, ComchipZener diodeSOT-233 pinsComchip
    What it is
    Zener diode
    Maker
    Comchip
    Package
    SOT-23
    Pins
    3
    Details
    25 V 0.35 mW zener diode
    Source
    Manufacturer datasheet

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

  • MMBZ5253BSOT-23Zener diode, 3 pins, DC ComponentsZener diodeSOT-233 pinsDC Components
    What it is
    Zener diode
    Maker
    DC Components
    Package
    SOT-23
    Pins
    3
    Source
    Manufacturer datasheet

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

  • MMBZ5253BTWSOT-363Zener diode, 6 pins, PanjitZener diodeSOT-3636 pinsPanjit
    What it is
    Zener diode
    Maker
    Panjit
    Package
    SOT-363
    Pins
    6
    Source
    Manufacturer datasheet

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

  • MMBZ5253BWSOT-323Zener diode, 3 pins, DC ComponentsZener diodeSOT-3233 pinsDC Components
    What it is
    Zener diode
    Maker
    DC Components
    Package
    SOT-323
    Pins
    3
    Source
    Manufacturer datasheet

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

  • MMST2222ASOT-323NPN transistor, 3 pins, Galaxy MicroelectronicsNPN transistorSOT-3233 pinsGalaxy Microelectronics
    What it is
    NPN transistor
    Maker
    Galaxy Microelectronics
    Package
    SOT-323
    Pins
    3
    Details
    40V, 0.6A, General Purpose NPN Bipolar Transistor
    Source
    Manufacturer datasheet

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

  • MMST2222A-HFSOT-323NPN transistor, 3 pins, ComchipNPN transistorSOT-3233 pinsComchip
    What it is
    NPN transistor
    Maker
    Comchip
    Package
    SOT-323
    Pins
    3
    Details
    40 V, 0.6 A NPN transistor
    Source
    Manufacturer datasheet

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

  • MMST2222AQSOT-323NPN transistor, 3 pins, Yangjie Electronic TechNPN transistorSOT-3233 pinsYangjie Electronic Tech
    What it is
    NPN transistor
    Maker
    Yangjie Electronic Tech
    Package
    SOT-323
    Pins
    3
    Source
    Manufacturer datasheet

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

  • MMSZ5253ASOD-123Zener diode, 2 pins, Galaxy MicroelectronicsZener diodeSOD-1232 pinsGalaxy Microelectronics
    What it is
    Zener diode
    Maker
    Galaxy Microelectronics
    Package
    SOD-123
    Pins
    2
    Details
    25V, 500mW, Surface Mount Zener Diodes
    Source
    Manufacturer datasheet

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

  • MMSZ5253ASSOD-323Zener diode, 2 pins, Galaxy MicroelectronicsZener diodeSOD-3232 pinsGalaxy Microelectronics
    What it is
    Zener diode
    Maker
    Galaxy Microelectronics
    Package
    SOD-323
    Pins
    2
    Details
    25V, 200mW, Surface Mount Zener Diodes
    Source
    Manufacturer datasheet

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

  • 3 more parts have no package on record
    • HFCN-1810+RF filter, Mini-CircuitsRF filterNot recordedNot recordedMini-Circuits
      What it is
      RF filter
      Maker
      Mini-Circuits
      Package
      Not recorded
      Pins
      Not recorded
      Details
      LTCC filter, 1950-4750 MHz
      Source
      Manufacturer datasheet

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

    • HFCN-1810D+RF filter, Mini-CircuitsRF filterNot recordedNot recordedMini-Circuits
      What it is
      RF filter
      Maker
      Mini-Circuits
      Package
      Not recorded
      Pins
      Not recorded
      Details
      LTCC filter, 1950-4750 MHz
      Source
      Manufacturer datasheet

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

    • MMBZ5253BWSZener diode, Taitron ComponentsZener diodeNot recordedNot recordedTaitron Components
      What it is
      Zener diode
      Maker
      Taitron Components
      Package
      Not recorded
      Pins
      Not recorded
      Details
      SMD Zener Diodes (Three Terminals) - 200mW
      Source
      Manufacturer datasheet

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

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.

Digital transistor

Ohms range, part lifted. The datasheet gives the built-in resistors: R1 in series with the base, R2 from base to emitter.

Working, it reads

Base to emitter reads about R1 plus R2 either way round, about 20 kΩ on a 10 k and 10 k part, give or take their wide tolerance. Collector to emitter reads open. A part with no R2 reads a junction behind R1 one way instead.

Dead, it reads

  • Collector to emitter the same both ways, near 0 Ω with a continuous beep: shorted.
  • From the base, open or far above R1 plus R2: R1 has failed. Static damage shows here most often.
  • Base to emitter near 0 Ω: failed short.
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:
The readings depend on the resistor values, so an identical part elsewhere on the board is the surest reference. Measure it the same way.
Watch for:
On the diode range a good part with 10 kΩ resistors reads open on every pair, so a good part looks dead there. Use the ohms range.

A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

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.

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