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SMD code X1p

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 X1 was searched.

82 parts are printed X1p

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.

  • Bft93SOT-23PNP transistor, 3 pins, InfineonPNP transistorSOT-233 pinsInfineon
    What it is
    PNP transistor
    Maker
    Infineon
    Package
    SOT-23
    Pins
    3
    Source
    Published code list

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

  • BFT93SOT-233 pins, InfineonNot recordedSOT-233 pinsInfineon
    What it is
    Not recorded
    Maker
    Infineon
    Package
    SOT-23
    Pins
    3
    Details
    equivalent BFQ23, BFQ24
    Source
    Published code list

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

  • BFT93WSOT-3233 pins, Philips SemiconductorsNot recordedSOT-3233 pinsPhilips Semiconductors
    What it is
    Not recorded
    Maker
    Philips Semiconductors
    Package
    SOT-323
    Pins
    3
    Details
    equivalent BFG23, BFQ23
    Source
    Published code list

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

  • BSD223PSOT-363Dual P-channel MOSFET, 6 pins, InfineonDual P-channel MOSFETSOT-3636 pinsInfineon
    What it is
    Dual P-channel MOSFET
    Maker
    Infineon
    Package
    SOT-363
    Pins
    6
    Source
    Published code list

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

  • BZF10C3V3SOD-123FZener diode, 2 pins, Diodesemi TechnologyZener diodeSOD-123F2 pinsDiodesemi Technology
    What it is
    Zener diode
    Maker
    Diodesemi Technology
    Package
    SOD-123F
    Pins
    2
    Details
    Zener diode: 3.1..3.5V, Izt=76mA, Zzt=10, 1W
    Source
    Published code list

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

  • BZT52-C51SOD-123Zener diode, 2 pins, VishayZener diodeSOD-1232 pinsVishay
    What it is
    Zener diode
    Maker
    Vishay
    Package
    SOD-123
    Pins
    2
    Source
    Published code list

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

  • BZT52B51SOD-123Zener diode, 2 pins, VishayZener diodeSOD-1232 pinsVishay
    What it is
    Zener diode
    Maker
    Vishay
    Package
    SOD-123
    Pins
    2
    Details
    Zener diode, VZ 51 V, 0.5 W
    Source
    An older or alternative marking, from a published code list

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

  • BZT52C51-VSOD-123Zener diode, 2 pins, VishayZener diodeSOD-1232 pinsVishay
    What it is
    Zener diode
    Maker
    Vishay
    Package
    SOD-123
    Pins
    2
    Details
    Zener diode: 51V±5%, Izt=5mA, Zzt=70, 500mW
    Source
    Published code list

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

  • BZV49-C27SOT-893 pins, InfineonNot recordedSOT-893 pinsInfineon
    What it is
    Not recorded
    Maker
    Infineon
    Package
    SOT-89
    Pins
    3
    Details
    Z-diode: 27V±5%, Izt=2mA, 1W
    Source
    Published code list

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

  • BZX84-C27SOT-23Zener diode, 3 pins, InfineonZener diodeSOT-233 pinsInfineon
    What it is
    Zener diode
    Maker
    Infineon
    Package
    SOT-23
    Pins
    3
    Details
    27 V approx. ±5% voltage regulator (Zener) diode
    Source
    Published code list

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

  • BZX84C27SOT-23Zener diode, 3 pins, Siemens / Zetex plcZener diodeSOT-233 pinsSiemens / Zetex plc
    What it is
    Zener diode
    Maker
    Siemens / Zetex plc
    Package
    SOT-23
    Pins
    3
    Source
    Published code list

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

  • BZX88-C27SOT-233 pins, Ferranti SemiconductorsNot recordedSOT-233 pinsFerranti Semiconductors
    What it is
    Not recorded
    Maker
    Ferranti Semiconductors
    Package
    SOT-23
    Pins
    3
    Details
    Z-diode: 27V±5%, 200mW
    Source
    Published code list

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

  • BZX384-C51SOD-323Zener diode, 2 pins, VishayZener diodeSOD-3232 pinsVishay
    What it is
    Zener diode
    Maker
    Vishay
    Package
    SOD-323
    Pins
    2
    Source
    Published code list

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

  • BZX384B51SOD-323Zener diode, 2 pins, VishayZener diodeSOD-3232 pinsVishay
    What it is
    Zener diode
    Maker
    Vishay
    Package
    SOD-323
    Pins
    2
    Source
    An older or alternative marking, from a published code list

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

  • BZX384C51-FSOD-323Zener diode, 2 pins, Taitron ComponentsZener diodeSOD-3232 pinsTaitron Components
    What it is
    Zener diode
    Maker
    Taitron Components
    Package
    SOD-323
    Pins
    2
    Details
    Zener diode: 48.0..54.0V, Izt=2.0mA, 200mW
    Source
    Published code list

    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.

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.

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.

P-channel MOSFET pair

Diode range, part lifted. Test drain to source first, then short gate to source and test again. Test each MOSFET on its own pins, as the datasheet's pinout gives them.

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.

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.

Silicon diode

Diode range, part lifted or one leg off the pad. Red probe on the anode.

Working, it reads

About 0.5 to 0.8 V anode to cathode, and open the other way. Small switching diodes read about 0.6 to 0.7 V; large rectifiers can read a little lower.

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: failed open.
  • A reading the wrong way round as well: 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 three-pin body can hold two diodes. With a common pin they read two junctions from that pin, just like a transistor; in series they read two drops end to end. Test each pair the datasheet names.

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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