Skip to content

SMD code M04 in SMA

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.

2 parts in SMA are printed M04

Not sure which one you have?

Answer up to 4 quick questions and these 6 parts are ranked, with a meter test that settles it. It works on a dead part too.

  • FM404SMARectifier, LRCRectifierLRC
    What it is
    Rectifier
    Maker
    LRC
    Package
    SMA
    Pins
    2
    Details
    Rectifier, VPK 400 V, IO @ TL 1 A, TL@°C 75
    Source
    Manufacturer datasheet

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

  • S-FM404SMARectifier, LRCRectifierLRC
    What it is
    Rectifier
    Maker
    LRC
    Package
    SMA
    Pins
    2
    Details
    Rectifier, VPK 400 V, IO @ TL 1 A, TL@°C 75
    Source
    Manufacturer datasheet

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

  • 4 more parts have no package on record. Nothing rules them out, so they stay.
    • CFM404Rectifier, LRCRectifierLRC
      What it is
      Rectifier
      Maker
      LRC
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Rectifier, VPK 400 V, IO @ TL 1 A, TL@°C 75
      Source
      Manufacturer datasheet

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

    • S-CFM404Rectifier, LRCRectifierLRC
      What it is
      Rectifier
      Maker
      LRC
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Rectifier, VPK 400 V, IO @ TL 1 A, TL@°C 75
      Source
      Manufacturer datasheet

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

    • S-CFM404-SRectifier, LRCRectifierLRC
      What it is
      Rectifier
      Maker
      LRC
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Rectifier, VPK 400 V, IO @ TL 1 A, TL@°C 75
      Source
      Manufacturer datasheet

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

    • QS6M4Complementary MOSFET pair (N-channel and P-channel), ROHMComplementary MOSFET pair (N-channel and P-channel)ROHM
      What it is
      Complementary MOSFET pair (N-channel and P-channel)
      Maker
      ROHM
      Package
      Not recorded
      Pins
      Not recorded
      Source
      Published code list

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

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.

MOSFET pair

Diode range, part lifted. Test drain to source first, then short gate to source and test again. Test each MOSFET on its own pins, as the datasheet's pinout gives them.

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.

Printed with a code easy to misread as M04

One character differs, and it is one that is easy to confuse under a lamp. Each code has a page of its own.

Codes that begin with M04

For a marking with its end worn or burnt off. Each code has a page of its own.

Did you find your part?

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