SMD code 81 in SOT-23
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.
6 parts in SOT-23 are printed 81
Not sure which one you have?
Answer up to 4 quick questions and these 18 parts are ranked, with a meter test that settles it. It works on a dead part too.
AP8822N-51GASOT-23Voltage supervisor, 3 pins, Anwell SemiconductorVoltage supervisor3 pinsAnwell Semiconductor
- What it is
- Voltage supervisor
- Maker
- Anwell Semiconductor
- Package
- SOT-23
- Pins
- 3
- Details
- Voltage detector IC: 5.1V±2%, -Reset ODO, Rdt=200ms, H-free
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
AP8822N-51PASOT-23Voltage supervisor, 3 pins, Anwell SemiconductorVoltage supervisor3 pinsAnwell Semiconductor
- What it is
- Voltage supervisor
- Maker
- Anwell Semiconductor
- Package
- SOT-23
- Pins
- 3
- Details
- Voltage detector IC: 5.1V±2%, -Reset ODO, Rdt=200ms
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
EC95810N51B1NSOT-23Voltage supervisor, 3 pins, E-CMOSVoltage supervisor3 pinsE-CMOS
- What it is
- Voltage supervisor
- Maker
- E-CMOS
- Package
- SOT-23
- Pins
- 3
- Details
- Voltage detector IC: 5.1V±2%, -Reset ODO, Rdt=200ms
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
ELM7531CBBSOT-23Voltage supervisor, 3 pins, ELM TechnologyVoltage supervisor3 pinsELM Technology
- What it is
- Voltage supervisor
- Maker
- ELM Technology
- Package
- SOT-23
- Pins
- 3
- Details
- Voltage detector IC: 3.1V±2%, +Reset PPO
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
ELM7531NBBSOT-23Voltage supervisor, 3 pins, ELM TechnologyVoltage supervisor3 pinsELM Technology
- What it is
- Voltage supervisor
- Maker
- ELM Technology
- Package
- SOT-23
- Pins
- 3
- Details
- Voltage detector IC: 3.1V±2%, +Reset ODO
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
MMBZ5266SOT-23Zener diode, 3 pins, VishayZener diode3 pinsVishay
- What it is
- Zener diode
- Maker
- Vishay
- Package
- SOT-23
- Pins
- 3
- Source
- Published code list
Is it dead? The meter test is below: Zener diode.
9 more parts have no package on record. Nothing rules them out, so they stay.
ULC0811CDNQESD protection diode, LeiditechESD protection diodeNot recordedLeiditech
- What it is
- ESD protection diode
- Maker
- Leiditech
- Package
- Not recorded
- Pins
- Not recorded
- Details
- ESD protection diode, VRWM 8 V, Cj 0.3 pF
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
AD5114BCPZ10-RL78 pins, Analog DevicesNot recorded8 pinsAnalog Devices
- What it is
- Not recorded
- Maker
- Analog Devices
- Package
- Not recorded
- Pins
- 8
- Source
- Published code list
Is it dead? The meter test is below: This part.
AP8822N-51GIVoltage supervisor, Anwell SemiconductorVoltage supervisorNot recordedAnwell Semiconductor
- What it is
- Voltage supervisor
- Maker
- Anwell Semiconductor
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Voltage detector IC: 5.1V±2%, -Reset ODO, 200ms Rt delay, H-free
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
AP8822N-51GSVoltage supervisor, Anwell SemiconductorVoltage supervisorNot recordedAnwell Semiconductor
- What it is
- Voltage supervisor
- Maker
- Anwell Semiconductor
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Voltage detector IC: 5.1V±2%, -Reset ODO, 200ms Rt delay, H-free
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
AP8822N-51PIVoltage supervisor, Anwell SemiconductorVoltage supervisorNot recordedAnwell Semiconductor
- What it is
- Voltage supervisor
- Maker
- Anwell Semiconductor
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Voltage detector IC: 5.1V±2%, -Reset ODO, 200ms Rt delay
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
AP8822N-51PSVoltage supervisor, Anwell SemiconductorVoltage supervisorNot recordedAnwell Semiconductor
- What it is
- Voltage supervisor
- Maker
- Anwell Semiconductor
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Voltage detector IC: 5.1V±2%, -Reset ODO, 200ms Rt delay
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
EC95810N51C7IVoltage supervisor, E-CMOSVoltage supervisorNot recordedE-CMOS
- What it is
- Voltage supervisor
- Maker
- E-CMOS
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Voltage detector IC: 5.1V±2%, -Reset ODO, Td=200ms
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
EC95810N51C7SVoltage supervisor, E-CMOSVoltage supervisorNot recordedE-CMOS
- What it is
- Voltage supervisor
- Maker
- E-CMOS
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Voltage detector IC: 5.1V±2%, -Reset ODO, Td=200ms
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
STP3481S6RGP-channel MOSFET, StansonP-channel MOSFETNot recordedStanson
- What it is
- P-channel MOSFET
- Maker
- Stanson
- Package
- Not recorded
- Pins
- Not recorded
- Details
- P-channel field effect transistor
- Source
- Published code list
Is it dead? The meter test is below: P-channel MOSFET.
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.
Zener diode
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
- 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.
TVS or ESD protection diode
Diode range, from the protected line to ground, part lifted if you can.
Working, it reads
A one-way part reads about 0.6 to 0.8 V forward and open in reverse. A two-way part reads open both ways. Arrays with several lines read as the datasheet's diagram draws them.
Dead, it reads
- From the line to ground, the same reading both ways, near 0 V with a continuous beep: shorted.
- A reading both ways on a one-way part: leaky.
- A one-way part open both ways: failed open.
- On the board
- , a line reading shorted to ground can be this part or anything else on that line. Lift it: if the short goes with it, it has failed.
- Compare:
- The same part on the next line or connector pin is the healthy reading to compare with.
- Watch for:
- A two-way part reads open both ways when it is good, exactly like one that has failed open. The meter cannot tell them apart; an identical part on the next line can.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
This part
Diode range and ohms range, part lifted.
Working, it reads
Depends on what it is. The datasheet, or an identical part, says.
Dead, it reads
- Between two pins, the same reading both ways, near 0 V with a continuous beep: shorted.
- Open between every pair of pins: failed open, or a part that reads open when working.
- 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.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
P-channel MOSFET
Diode range, part lifted. Test drain to source first, then short gate to source and test again.
Working, it reads
Red probe on the drain, black on the source: about 0.4 to 0.9 V, the body diode. Open the other way. The gate reads open to both other pins, both ways.
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. Often all three pins end up shorted together.
- No body diode at all: failed open.
- On the board
- the gate usually has a resistor to the source, so gate to source reads that resistor, which 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 81
One character differs, and it is one that is easy to confuse under a lamp. Each code has a page of its own.
Codes not listed here are printed on 2 more parts.
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