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SMD marking

K8in SOD-123W

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 K8

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.

  • PMEG10020ELRSOD-123WSchottky diode, Nexperia
    What it is
    Schottky diode
    Maker
    Nexperia
    Package
    SOD-123W
    Pins
    2
    Details
    100 V, 2 A low leakage current 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 PMEG10020ELR, opens in a new tab
  • 1 more part has no package on record. Nothing rules them out, so they stay.
    • BZT52C6V8KZener diode, Taiwan Semiconductor
      What it is
      Zener diode
      Maker
      Taiwan Semiconductor
      Package
      Not recorded
      Pins
      Not recorded
      Source
      From the manufacturer's datasheet

      Is it dead?

      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:
      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.

      Datasheetfor BZT52C6V8K, opens in a new tab
1 more part is printed with a code easy to misread as K8

Printed with a code easy to misread

One character differs, and it is one that is easy to confuse under a lamp. The odd one out is marked on each.

  • BG3230printed KBRF amplifier (MMIC), Infineon

    Printed KB on the part. Easy to misread as K8. Check that character with a loupe before you order anything.

    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 BG3230, opens in a new tab

Open this in the search to correct a character or try another package.