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SMD code 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.

85 parts are printed 23-

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.

  • DTC143EUASOT-323Digital transistor (NPN, resistors built in), 3 pins, Formosa MicrosemiDigital transistor (NPN, resistors built in)SOT-3233 pinsFormosa Microsemi
    What it is
    Digital transistor (NPN, resistors built in)
    Maker
    Formosa Microsemi
    Package
    SOT-323
    Pins
    3
    Details
    NPN digital transistor (bias resistors built in)
    Source
    Manufacturer datasheet

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

  • DTC143EUA-Q1SOT-323Digital transistor (NPN, resistors built in), 3 pins, Formosa MicrosemiDigital transistor (NPN, resistors built in)SOT-3233 pinsFormosa Microsemi
    What it is
    Digital transistor (NPN, resistors built in)
    Maker
    Formosa Microsemi
    Package
    SOT-323
    Pins
    3
    Source
    Manufacturer datasheet

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

  • DTC143EUBSOT-323Digital transistor (NPN, resistors built in), 3 pins, ROHMDigital transistor (NPN, resistors built in)SOT-3233 pinsROHM
    What it is
    Digital transistor (NPN, resistors built in)
    Maker
    ROHM
    Package
    SOT-323
    Pins
    3
    Details
    NPN digital transistor (bias resistor built-in); R1 = 4.7kOhm, R2 = 4.7kOhm
    Source
    Manufacturer datasheet

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

  • EMB50P03JSOT-23P-channel MOSFET, 3 pins, Excelliance MOSP-channel MOSFETSOT-233 pinsExcelliance MOS
    What it is
    P-channel MOSFET
    Maker
    Excelliance MOS
    Package
    SOT-23
    Pins
    3
    Details
    30 V, 4.5 A P-channel MOSFET
    Source
    Manufacturer datasheet

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

  • EMB50P03KSOT-23-6P-channel MOSFET, 6 pins, Excelliance MOSP-channel MOSFETSOT-23-66 pinsExcelliance MOS
    What it is
    P-channel MOSFET
    Maker
    Excelliance MOS
    Package
    SOT-23-6
    Pins
    6
    Details
    30 V, 5 A P-channel MOSFET
    Source
    Manufacturer datasheet

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

  • HDDTC143ECA7FSOT-23Digital transistor (NPN, resistors built in), 3 pins, HXYDigital transistor (NPN, resistors built in)SOT-233 pinsHXY
    What it is
    Digital transistor (NPN, resistors built in)
    Maker
    HXY
    Package
    SOT-23
    Pins
    3
    Details
    Digital transistor (bias resistors built in)
    Source
    Manufacturer datasheet

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

  • HRN1101LXHFSOT-523Digital transistor (NPN, resistors built in), 3 pins, HXYDigital transistor (NPN, resistors built in)SOT-5233 pinsHXY
    What it is
    Digital transistor (NPN, resistors built in)
    Maker
    HXY
    Package
    SOT-523
    Pins
    3
    Details
    Digital transistor (bias resistors built in)
    Source
    Manufacturer datasheet

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

  • HTDTC143ELMSOT-23Digital transistor (NPN, resistors built in), 3 pins, HXYDigital transistor (NPN, resistors built in)SOT-233 pinsHXY
    What it is
    Digital transistor (NPN, resistors built in)
    Maker
    HXY
    Package
    SOT-23
    Pins
    3
    Details
    Digital transistor (bias resistors built in)
    Source
    Manufacturer datasheet

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

  • LD5523GLSOT-23-6AC-DC controller, 6 pins, LeadtrendAC-DC controllerSOT-23-66 pinsLeadtrend
    What it is
    AC-DC controller
    Maker
    Leadtrend
    Package
    SOT-23-6
    Pins
    6
    Details
    Multi-Mode PWM Controller of Flyback with Integrated BNI/BNO and Protection
    Source
    Manufacturer datasheet

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

  • LMBR230FT1GSOD-123FSchottky diode, 2 pins, LRCSchottky diodeSOD-123F2 pinsLRC
    What it is
    Schottky diode
    Maker
    LRC
    Package
    SOD-123F
    Pins
    2
    Details
    Schottky diode, VR 30 V, IF 2 A, VF Max 0.5 V
    Source
    Manufacturer datasheet

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

  • MMBT3646SOT-23NPN transistor, 3 pins, onsemiNPN transistorSOT-233 pinsonsemi
    What it is
    NPN transistor
    Maker
    onsemi
    Package
    SOT-23
    Pins
    3
    Details
    NPN Switching Transistor
    Source
    Manufacturer datasheet

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

  • MMUN2232LT1GSOT-23Digital transistor (NPN, resistors built in), 3 pins, HXYDigital transistor (NPN, resistors built in)SOT-233 pinsHXY
    What it is
    Digital transistor (NPN, resistors built in)
    Maker
    HXY
    Package
    SOT-23
    Pins
    3
    Details
    Digital transistor (bias resistors built in)
    Source
    Manufacturer datasheet

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

  • NUF2230XV6SOT-563ESD protection diode, 6 pins, onsemiESD protection diodeSOT-5636 pinsonsemi
    What it is
    ESD protection diode
    Maker
    onsemi
    Package
    SOT-563
    Pins
    6
    Details
    2 Line EMI Filter with ESD Protection
    Source
    Manufacturer datasheet

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

  • 2 more parts have no package on record
    • LMBR230ET1GSchottky diode, LRCSchottky diodeNot recordedNot recordedLRC
      What it is
      Schottky diode
      Maker
      LRC
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Schottky diode, VR 30 V, IF 2 A, VF Max 0.58 V
      Source
      Manufacturer datasheet

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

    • LNB2306ELT1GN-channel MOSFET, LRCN-channel MOSFETNot recordedNot recordedLRC
      What it is
      N-channel MOSFET
      Maker
      LRC
      Package
      Not recorded
      Pins
      Not recorded
      Details
      MOSFET, N-Channel(with ESD), VDSS 30 V, VGS 20 V
      Source
      Manufacturer datasheet

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

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.

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.

P-channel MOSFET

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

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.

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.

N-channel MOSFET

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

Working, it reads

Red probe on the source, black on the drain: 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. A drain short can be the load. 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.

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.

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.

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