SMD code 3A
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.
12 parts are printed 3A
Not sure which one you have?
Answer up to 4 quick questions and these 12 parts are ranked, with a meter test that settles it. It works on a dead part too.
1N4448WSSOD-323Switching diode, 2 pins, VishaySwitching diodeSOD-3232 pinsVishay
- What it is
- Switching diode
- Maker
- Vishay
- Package
- SOD-323
- Pins
- 2
- Details
- Switching diode, 75 V, 250 mA
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: Silicon diode.
BC856SOT-23PNP transistor, 3 pins, InfineonPNP transistorSOT-233 pinsInfineon
- What it is
- PNP transistor
- Maker
- Infineon
- Package
- SOT-23
- Pins
- 3
- Details
- 65 V, 100 mA PNP general-purpose transistor
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: PNP transistor.
BC856ASOT-23PNP transistor, 3 pins, NexperiaPNP transistorSOT-233 pinsNexperia
- What it is
- PNP transistor
- Maker
- Nexperia
- Package
- SOT-23
- Pins
- 3
- Pinout
- 1 base
- 2 emitter
- 3 collector
- Details
- -80 V PNP small-signal transistor, gain group A
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: PNP transistor.
BC856AWSOT-323Transistor, 3 pins, DiotecTransistorSOT-3233 pinsDiotec
- What it is
- Transistor
- Maker
- Diotec
- Package
- SOT-323
- Pins
- 3
- Details
- SMD General Purpose PNP Transistors
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: Bipolar transistor.
BCM847BVSOT-563NPN transistor, 6 pins, NexperiaNPN transistorSOT-5636 pinsNexperia
- What it is
- NPN transistor
- Maker
- Nexperia
- Package
- SOT-563
- Pins
- 6
- Details
- NPN/NPN matched double transistor
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: NPN transistor.
MM3Z43SOD-323Zener diode, 2 pins, DiotecZener diodeSOD-3232 pinsDiotec
- What it is
- Zener diode
- Maker
- Diotec
- Package
- SOD-323
- Pins
- 2
- Details
- SMD Planar Zener Diodes
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: Zener diode.
NX3020NAKWSOT-323N-channel MOSFET, 3 pins, NexperiaN-channel MOSFETSOT-3233 pinsNexperia
- What it is
- N-channel MOSFET
- Maker
- Nexperia
- Package
- SOT-323
- Pins
- 3
- Details
- 30 V, 180 mA N-channel Trench MOSFET
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: N-channel MOSFET.
PJSOT08SOT-23ESD protection diode, 3 pins, PanjitESD protection diodeSOT-233 pinsPanjit
- What it is
- ESD protection diode
- Maker
- Panjit
- Package
- SOT-23
- Pins
- 3
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
PMBD7100SOT-23Switching diode, 3 pins, NexperiaSwitching diodeSOT-233 pinsNexperia
- What it is
- Switching diode
- Maker
- Nexperia
- Package
- SOT-23
- Pins
- 3
- Details
- High-speed double diode
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: Silicon diode.
TPS389030DSEWSONVoltage supervisor, 6 pins, Texas InstrumentsVoltage supervisorWSON6 pinsTexas Instruments
- What it is
- Voltage supervisor
- Maker
- Texas Instruments
- Package
- WSON
- Pins
- 6
- Details
- Low Quiescent Current, 1% Accurate Supervisor with Programmable Delay
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: Integrated circuit.
2 more parts have no package on record
ESDBM3V3AE1ESD protection diode, JSCJESD protection diodeNot recordedNot recordedJSCJ
- What it is
- ESD protection diode
- Maker
- JSCJ
- Package
- Not recorded
- Pins
- Not recorded
- Details
- ESD protection diode, VRWM 3.3 V
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
VBUS03N1-HD1ESD protection diode, VishayESD protection diodeNot recordedNot recordedVishay
- What it is
- ESD protection diode
- Maker
- Vishay
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Ultra Low Capacitance Unidirectional Single Line ESD Protection Diode in DFN1006-2A
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
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.
PNP transistor
Diode range, part lifted or its base leg off the pad.
Working, it reads
Black probe on the base 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.
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.
NPN transistor
Diode range, part lifted or its base leg off the pad.
Working, it reads
Red probe on the base 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.
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.
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.
N-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 source, black on the drain: 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. A drain short can be the load. 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.
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.
Codes that begin with 3A
For a marking with its end worn or burnt off. Each code has a page of its own.
Open this in the search to correct a character or try another package.