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SMD marking

KAin SOD-523

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.

2 parts are printed KA

Not sure which one you have?

Answer up to 4 quick questions and these 2 parts are ranked, with a meter test that settles it. It works on a dead part too.

  • PMEG3010EBSOD-523Schottky diode, Nexperia
    What it is
    Schottky diode
    Maker
    Nexperia
    Package
    SOD-523
    Pins
    2
    Details
    30 V, 1 A very low VF Schottky barrier rectifier
    Source
    From the manufacturer's datasheet

    Is it dead?

    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:
    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.

    Datasheetfor PMEG3010EB, opens in a new tab
  • 1 more part has no package on record. Nothing rules them out, so they stay.
    • BG3130RF amplifier (MMIC), Infineon
      What it is
      RF amplifier (MMIC)
      Maker
      Infineon
      Package
      Not recorded
      Pins
      Not recorded
      Source
      From the manufacturer's datasheet

      Is it dead?

      Voltage, board powered, on the output pin that the bias resistor or choke feeds.

      Working, it reads

      The output pin sits at the device voltage the datasheet gives, a few volts, below the supply.

      Dead, it reads

      • Output pin at 0 V, or near 0 Ω to ground with the power off: shorted inside.
      • Output pin at the full supply voltage: open inside, no current flowing.
      On the board:
      Measured on the board with power on; the bias network is part of the reading.
      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 figures depend on the part and its bias resistor. The datasheet gives both.

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

      Datasheetfor BG3130, opens in a new tab
1 more part has a code that begins with KA

Codes that begin with KA

For a marking with its end worn or burnt off. Each one shows its full printed code.

  • MMBD4148CTprinted KA4Switching diode, JSCJ

    Printed KA4. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

    What it is
    Switching diode
    Maker
    JSCJ
    Package
    Not recorded
    Pins
    Not recorded
    Details
    Switching diode, 75 V, 150 mA
    Source
    From the manufacturer's datasheet

    Is it dead?

    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:
    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.

    Datasheetfor MMBD4148CT, opens in a new tab

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