SMD code M9 in SOT-343

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.

3 parts in SOT-343 are printed M9

Not sure which one you have?

Answer up to 4 quick questions and these 22 parts are ranked, with a meter test that settles it. It works on a dead part too.

R3111Q291ASOT-3434 pins, RicohNot recorded4 pinsRicoh
What it is
Not recorded
Maker
Ricoh
Package
SOT-343
Pins
4
Details
CMOS-IC: Voltage Detector 2,9V±2.0%, Reset Push-pull output
Source
Published code list
Is it dead? The meter test is below: Integrated circuit.
R3116Q261ASOT-343Voltage supervisor, 4 pins, RicohVoltage supervisor4 pinsRicoh
What it is
Voltage supervisor
Maker
Ricoh
Package
SOT-343
Pins
4
Details
Voltage detector IC: 2.6V±0.8%, -Reset ODO
Source
Published code list
Is it dead? The meter test is below: Integrated circuit.
RP104Q231BSOT-343LDO regulator, 4 pins, RicohLDO regulator4 pinsRicoh
What it is
LDO regulator
Maker
Ricoh
Package
SOT-343
Pins
4
Details
Linear voltage regulator IC: LDO, 2.3V±0.8%, 150mA,
Source
Published code list
Is it dead? The meter test is below: Voltage regulator.
12 more parts have no package on record. Nothing rules them out, so they stay.
- LDTC113YET1GDigital transistor (NPN, resistors built in), LRCDigital transistor (NPN, resistors built in)Not recordedLRC
  What it is
  Digital transistor (NPN, resistors built in)
  Maker
  LRC
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Digital transistor (bias resistors built in), NPN, IC 100 mA, VCEO 50 V
  Source
  Manufacturer datasheet
  Is it dead? The meter test is below: Digital transistor.
  Datasheetfor LDTC113YET1G, opens in a new tab
- 2SC5096FT-RRF transistor, ToshibaRF transistorNot recordedToshiba
  What it is
  RF transistor
  Maker
  Toshiba
  Package
  Not recorded
  Pins
  Not recorded
  Details
  NPN transistor: VHF/UHF, LN, 20V, 15mA, 100mW, 10GHz, B=50..100
  Source
  Published code list
  Is it dead? The meter test is below: Bipolar transistor.
- AP8821N-49GIVoltage supervisor, Anwell SemiconductorVoltage supervisorNot recordedAnwell Semiconductor
  What it is
  Voltage supervisor
  Maker
  Anwell Semiconductor
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Voltage detector IC: 4.9V±2%, -Reset ODO, H-free
  Source
  Published code list
  Is it dead? The meter test is below: Integrated circuit.
- AP8821N-49GSVoltage supervisor, Anwell SemiconductorVoltage supervisorNot recordedAnwell Semiconductor
  What it is
  Voltage supervisor
  Maker
  Anwell Semiconductor
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Voltage detector IC: 4.9V±2%, -Reset ODO, H-free
  Source
  Published code list
  Is it dead? The meter test is below: Integrated circuit.
- AP8821N-49PIVoltage supervisor, Anwell SemiconductorVoltage supervisorNot recordedAnwell Semiconductor
  What it is
  Voltage supervisor
  Maker
  Anwell Semiconductor
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Voltage detector IC: 4.9V±2%, -Reset ODO
  Source
  Published code list
  Is it dead? The meter test is below: Integrated circuit.
- AP8821N-49PSVoltage supervisor, Anwell SemiconductorVoltage supervisorNot recordedAnwell Semiconductor
  What it is
  Voltage supervisor
  Maker
  Anwell Semiconductor
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Voltage detector IC: 4.9V±2%, -Reset ODO
  Source
  Published code list
  Is it dead? The meter test is below: Integrated circuit.
- BD46E321G-MVoltage supervisor, ROHMVoltage supervisorNot recordedROHM
  What it is
  Voltage supervisor
  Maker
  ROHM
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Voltage detector IC: 3.2V±1%, -MR, -Reset PPO, Rdt=100ms
  Source
  Published code list
  Is it dead? The meter test is below: Integrated circuit.
- BU19UB3WGLDO regulator, ROHMLDO regulatorNot recordedROHM
  What it is
  LDO regulator
  Maker
  ROHM
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Linear voltage regulator IC: LDO, 1.9V±1%, 360mA, +CE
  Source
  Published code list
  Is it dead? The meter test is below: Voltage regulator.
- EC95808N49C7IVoltage supervisor, E-CMOSVoltage supervisorNot recordedE-CMOS
  What it is
  Voltage supervisor
  Maker
  E-CMOS
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Voltage detector IC: 4.9V±2%, -Reset ODO
  Source
  Published code list
  Is it dead? The meter test is below: Integrated circuit.
- EC95808N49C7SVoltage supervisor, E-CMOSVoltage supervisorNot recordedE-CMOS
  What it is
  Voltage supervisor
  Maker
  E-CMOS
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Voltage detector IC: 4.9V±2%, -Reset ODO
  Source
  Published code list
  Is it dead? The meter test is below: Integrated circuit.
- IXD5120N392NR-GVoltage supervisor, IXYSVoltage supervisorNot recordedIXYS
  What it is
  Voltage supervisor
  Maker
  IXYS
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Voltage detector IC: 3.9V±2% -Reset ODO
  Source
  Published code list
  Is it dead? The meter test is below: Integrated circuit.
- R1100D191CNisshinbo Micro DevicesNot recordedNot recordedNisshinbo Micro Devices
  What it is
  Not recorded
  Maker
  Nisshinbo Micro Devices
  Package
  Not recorded
  Pins
  Not recorded
  Details
  VR-IC: U-low Icc, 1.9V±2%, 180mA
  Source
  Published code list
  Is it dead? The meter test is below: Integrated circuit.

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.

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.

Digital transistor

Ohms range, part lifted. The datasheet gives the built-in resistors: R1 in series with the base, R2 from base to emitter.

Working, it reads

Base to emitter reads about R1 plus R2 either way round, about 20 kΩ on a 10 k and 10 k part, give or take their wide tolerance. Collector to emitter reads open. A part with no R2 reads a junction behind R1 one way instead.

Dead, it reads

Collector to emitter the same both ways, near 0 Ω with a continuous beep: shorted.
From the base, open or far above R1 plus R2: R1 has failed. Static damage shows here most often.
Base to emitter near 0 Ω: failed short.

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:: The readings depend on the resistor values, so an identical part elsewhere on the board is the surest reference. Measure it the same way.
Watch for:: On the diode range a good part with 10 kΩ resistors reads open on every pair, so a good part looks dead there. Use the ohms range.

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

Bipolar transistor

Diode range, part lifted or its base leg off the pad.

Working, it reads

From the base, one probe colour reads about 0.6 to 0.75 V to the emitter and to the collector, and open the other way round. Collector to emitter reads open both ways.

Dead, it reads

Collector to emitter the same both ways, near 0 V with a continuous beep: shorted. The commonest failure.
The base the same both ways to another pin, near 0 V or a middling value: a shorted junction.
Only one junction reads, or none: a junction has failed open. It then looks like a diode.
A reading the wrong way round, where it should be open: 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 pair of diodes with a common pin reads just like a transistor, and some transistors carry a built-in diode or resistor. The datasheet says which.

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

Codes that begin with M9

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

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