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SMD code ML

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

  • 7UL1G17FSSOT-9535 pins, ToshibaNot recordedSOT-9535 pinsToshiba
    What it is
    Not recorded
    Maker
    Toshiba
    Package
    SOT-953
    Pins
    5
    Details
    CMOS logic IC: Buffer with Schmitt-trigger input
    Source
    Published code list

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

  • 7UL1G17FUSOT-3535 pins, ToshibaNot recordedSOT-3535 pinsToshiba
    What it is
    Not recorded
    Maker
    Toshiba
    Package
    SOT-353
    Pins
    5
    Details
    CMOS logic IC: Buffer with Schmitt-trigger input
    Source
    Published code list

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

  • ASM162RCUSFSOT-143Voltage supervisor, 4 pins, PulseCore SemiconductorVoltage supervisorSOT-1434 pinsPulseCore Semiconductor
    What it is
    Voltage supervisor
    Maker
    PulseCore Semiconductor
    Package
    SOT-143
    Pins
    4
    Details
    Voltage detector IC: 2.63V±2%, -MR, +Reset ODO, Lead-free
    Source
    Published code list

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

  • BF994SRSOT-1434 pins, VALVO GmbHNot recordedSOT-1434 pinsVALVO GmbH
    What it is
    Not recorded
    Maker
    VALVO GmbH
    Package
    SOT-143
    Pins
    4
    Details
    equivalent BF964S
    Source
    Published code list

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

  • CH751WSPTSOT-323Schottky diode, 3 pins, Chenmko EnterpriseSchottky diodeSOT-3233 pinsChenmko Enterprise
    What it is
    Schottky diode
    Maker
    Chenmko Enterprise
    Package
    SOT-323
    Pins
    3
    Details
    Diode: Dual, SBR, 40V, 30mA, Vf<0.37V(1mA)
    Source
    Published code list

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

  • DDZ9714SOD-123Zener diode, 2 pins, Diodes IncorporatedZener diodeSOD-1232 pinsDiodes Incorporated
    What it is
    Zener diode
    Maker
    Diodes Incorporated
    Package
    SOD-123
    Pins
    2
    Details
    Z-diode: 33V±5%, 500mW
    Source
    Published code list

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

  • DDZ9714SSOD-323Zener diode, 2 pins, Diodes IncorporatedZener diodeSOD-3232 pinsDiodes Incorporated
    What it is
    Zener diode
    Maker
    Diodes Incorporated
    Package
    SOD-323
    Pins
    2
    Details
    Z-diode: 33V±5%, 200mW
    Source
    Published code list

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

  • DDZ9714TSOD-523Zener diode, 2 pins, Diodes IncorporatedZener diodeSOD-5232 pinsDiodes Incorporated
    What it is
    Zener diode
    Maker
    Diodes Incorporated
    Package
    SOD-523
    Pins
    2
    Details
    Zener diode: 33V±1%, If=10mA, 150mW
    Source
    Published code list

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

  • DDZX9714SOT-23Zener diode, 3 pins, Diodes IncorporatedZener diodeSOT-233 pinsDiodes Incorporated
    What it is
    Zener diode
    Maker
    Diodes Incorporated
    Package
    SOT-23
    Pins
    3
    Details
    Z-diode: 33V±5%, 500mW
    Source
    Published code list

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

  • DDZX9714TSSOT-3636 pins, Diodes IncorporatedNot recordedSOT-3636 pinsDiodes Incorporated
    What it is
    Not recorded
    Maker
    Diodes Incorporated
    Package
    SOT-363
    Pins
    6
    Details
    Z-diode: Triple, 3x33V±5%, 200mW
    Source
    Published code list

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

  • DDZX9714WSOT-3233 pins, Diodes IncorporatedNot recordedSOT-3233 pinsDiodes Incorporated
    What it is
    Not recorded
    Maker
    Diodes Incorporated
    Package
    SOT-323
    Pins
    3
    Details
    Z-diode: 33V±5%, 200mW
    Source
    Published code list

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

  • 4 more parts have no package on record
    • BD5230FVEVoltage supervisor, ROHMVoltage supervisorNot recordedNot recordedROHM
      What it is
      Voltage supervisor
      Maker
      ROHM
      Package
      Not recorded
      Pins
      Not recorded
      Details
      CMOS-IC: Voltage Detector 3V, Reset Open drain output
      Source
      Published code list

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

    • BD5230GVoltage supervisor, ROHMVoltage supervisorNot recordedNot recordedROHM
      What it is
      Voltage supervisor
      Maker
      ROHM
      Package
      Not recorded
      Pins
      Not recorded
      Details
      CMOS-IC: Voltage Detector 3V, Reset Open drain output
      Source
      Published code list

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

    • BF1211WRNXPNot recordedNot recordedNot recordedNXP
      What it is
      Not recorded
      Maker
      NXP
      Package
      Not recorded
      Pins
      Not recorded
      Details
      n-ch dg uhf mosfet, 5V
      Source
      Published code list

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

    • BF1212WR4 pins, Philips SemiconductorsNot recordedNot recorded4 pinsPhilips Semiconductors
      What it is
      Not recorded
      Maker
      Philips Semiconductors
      Package
      Not recorded
      Pins
      4
      Source
      Published code list

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

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.

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.

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.

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.

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.

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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