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SMD code X3 in SOT-89

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

  • BZV49-C33SOT-89InfineonNot recordedInfineon
    What it is
    Not recorded
    Maker
    Infineon
    Package
    SOT-89
    Pins
    3
    Details
    Z-diode: 33V±5%, Izt=2mA, 1W
    Source
    Published code list

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

  • ELM7553CABSOT-89Voltage supervisor, ELM TechnologyVoltage supervisorELM Technology
    What it is
    Voltage supervisor
    Maker
    ELM Technology
    Package
    SOT-89
    Pins
    3
    Details
    Voltage detector IC: 5.3V±2%, +Reset PPO
    Source
    Published code list

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

  • ELM7553NABSOT-89Voltage supervisor, ELM TechnologyVoltage supervisorELM Technology
    What it is
    Voltage supervisor
    Maker
    ELM Technology
    Package
    SOT-89
    Pins
    3
    Details
    Voltage detector IC: 5.3V±2%, +Reset ODO
    Source
    Published code list

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

  • 12 more parts have no package on record. Nothing rules them out, so they stay.
    • FMOSAE014N02MOSFET, Formosa MicrosemiMOSFETFormosa Microsemi
      What it is
      MOSFET
      Maker
      Formosa Microsemi
      Package
      Not recorded
      Pins
      Not recorded
      Source
      Manufacturer datasheet

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

    • TST011C-378WSSchottky diode, Taitron ComponentsSchottky diodeTaitron Components
      What it is
      Schottky diode
      Maker
      Taitron Components
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Schottky Barrier Diodes (Multiple Terminals)
      Source
      Manufacturer datasheet

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

    • TST011C-378WTSchottky diode, Taitron ComponentsSchottky diodeTaitron Components
      What it is
      Schottky diode
      Maker
      Taitron Components
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Schottky Barrier Diodes (Multiple Terminals)
      Source
      Manufacturer datasheet

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

    • VSKY033085Schottky diode, VishaySchottky diodeVishay
      What it is
      Schottky diode
      Maker
      Vishay
      Package
      Not recorded
      Pins
      Not recorded
      Details
      X3
      Source
      Manufacturer datasheet

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

    • ZGFM103V9B-MSZener diode, Formosa MicrosemiZener diodeFormosa Microsemi
      What it is
      Zener diode
      Maker
      Formosa Microsemi
      Package
      Not recorded
      Pins
      Not recorded
      Source
      Manufacturer datasheet

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

    • ZGFM103V9B-MS-Q1Zener diode, Formosa MicrosemiZener diodeFormosa Microsemi
      What it is
      Zener diode
      Maker
      Formosa Microsemi
      Package
      Not recorded
      Pins
      Not recorded
      Source
      Manufacturer datasheet

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

    • ZGFM103V9B-MSTZener diode, Formosa MicrosemiZener diodeFormosa Microsemi
      What it is
      Zener diode
      Maker
      Formosa Microsemi
      Package
      Not recorded
      Pins
      Not recorded
      Source
      Manufacturer datasheet

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

    • ZGFM103V9B-MST-Q1Zener diode, Formosa MicrosemiZener diodeFormosa Microsemi
      What it is
      Zener diode
      Maker
      Formosa Microsemi
      Package
      Not recorded
      Pins
      Not recorded
      Source
      Manufacturer datasheet

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

    • 74LVC2G06FX4Diodes IncorporatedNot recordedDiodes Incorporated
      What it is
      Not recorded
      Maker
      Diodes Incorporated
      Package
      Not recorded
      Pins
      Not recorded
      Details
      CMOS logic IC: Dual inverter buffer/driver (ODO)
      Source
      Published code list

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

    • BD46392GVoltage supervisor, ROHMVoltage supervisorROHM
      What it is
      Voltage supervisor
      Maker
      ROHM
      Package
      Not recorded
      Pins
      Not recorded
      Details
      CMOS-IC: Voltage Detector 3,9V, -Reset Push-pull output, 200ms
      Source
      Published code list

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

    • R1163D231DNisshinbo Micro DevicesNot recordedNisshinbo Micro Devices
      What it is
      Not recorded
      Maker
      Nisshinbo Micro Devices
      Package
      Not recorded
      Pins
      Not recorded
      Details
      VR-IC: LDO, CE, auto-discharge, 2.3V±1.5%, 150mA
      Source
      Published code list

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

    • RN1131FDigital transistor (NPN, resistors built in), ToshibaDigital transistor (NPN, resistors built in)Toshiba
      What it is
      Digital transistor (NPN, resistors built in)
      Maker
      Toshiba
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Si-npn-Digi: Sw, 50V, 100mA, 100mW, R1=100k
      Source
      Published code list

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

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.

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.

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.

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.

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.

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.

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.

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.

Codes that begin with X3

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 91 more parts.

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