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SMD code 812M

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.

812M on a chip resistor

812 MΩ

812 MΩ resistor

The M is both the decimal point and the multiplier: 812 MΩ.

Check it with a meter

Lift one end and measure across it. A good one reads 812 MΩ. Measuring it in circuit reads the parallel combination of everything around it, which is almost always lower, never higher: well above 812 MΩ on the board is a fault. Open, or well above 812 MΩ, means it has failed: burnt, cracked or corroded. That does not change what to fit: the marking still says 812 MΩ. A burnt resistor usually means the part it feeds drew too much, so find that before fitting a new one.

On a transistor or diode body (SOT-23-5, SOT-143, SOT-353), 812M is a part code instead. Those parts are listed below.

5 parts are printed 812M

Not sure which one you have?

Answer up to 4 quick questions and these 5 parts are ranked, with a meter test that settles it. It works on a dead part too.

  • EC8908-12MW1WSONLDO regulator, E-CMOSLDO regulatorWSONNot recordedE-CMOS
    What it is
    LDO regulator
    Maker
    E-CMOS
    Package
    WSON
    Pins
    Not recorded
    Details
    Linear voltage regulator IC: LDO, 1.2V±1%, 700mA, +CE
    Source
    Published code list

    Is it dead? The meter test is below: Voltage regulator.

  • EC890812MC5SOT-353LDO regulator, 5 pins, E-CMOSLDO regulatorSOT-3535 pinsE-CMOS
    What it is
    LDO regulator
    Maker
    E-CMOS
    Package
    SOT-353
    Pins
    5
    Details
    Linear voltage regulator IC: LDO, 1.2V±1%, 700mA, +CE
    Source
    Published code list

    Is it dead? The meter test is below: Voltage regulator.

  • SGM812-MXKA4SOT-143Voltage supervisor, 4 pins, SG MicroVoltage supervisorSOT-1434 pinsSG Micro
    What it is
    Voltage supervisor
    Maker
    SG Micro
    Package
    SOT-143
    Pins
    4
    Details
    Voltage detector IC: 4.38V±1.5%, +Reset ODO, -MR
    Source
    Published code list

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

  • SGM812-MXN5SOT-23-5Voltage supervisor, 5 pins, SG MicroVoltage supervisorSOT-23-55 pinsSG Micro
    What it is
    Voltage supervisor
    Maker
    SG Micro
    Package
    SOT-23-5
    Pins
    5
    Details
    Voltage detector IC: 4.38V±1.5%, +Reset ODO, -MR
    Source
    Published code list

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

  • 1 more part has no package on record
    • EC890812MC7LDO regulator, E-CMOSLDO regulatorNot recordedNot recordedE-CMOS
      What it is
      LDO regulator
      Maker
      E-CMOS
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Linear voltage regulator IC: LDO, 1.2V±1%, 700mA, +CE
      Source
      Published code list

      Is it dead? The meter test is below: Voltage regulator.

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.

Voltage regulator

Voltage, board powered, black probe on ground. Then ohms with the power off.

Working, it reads

Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

Dead, it reads

  • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
  • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
  • Power off, input to output near 0 Ω: shorted.
On the board:
An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
Compare:
The same regulator on another rail or another board shows the right voltages and the right resistances.
Watch for:
Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

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.

Did you find your part?

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