SMD code A2-
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.
267 parts are printed A2-
Not sure which one you have?
Answer up to 4 quick questions and these 50 parts are ranked, with a meter test that settles it. It works on a dead part too.
MMBD4148WSOT-323Switching diode, 3 pins, HottechSwitching diodeSOT-3233 pinsHottech
- What it is
- Switching diode
- Maker
- Hottech
- Package
- SOT-323
- Pins
- 3
- Details
- Switching diode, 75 V
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
MMDT3906SOT-363PNP transistor, 6 pins, Blue RocketPNP transistorSOT-3636 pinsBlue Rocket
- What it is
- PNP transistor
- Maker
- Blue Rocket
- Package
- SOT-363
- Pins
- 6
- Details
- PNP bipolar transistor
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: PNP transistor.
MMDT3906-CSOT-363Transistor, 6 pins, SeCoSTransistorSOT-3636 pinsSeCoS
- What it is
- Transistor
- Maker
- SeCoS
- Package
- SOT-363
- Pins
- 6
- Details
- Bipolar transistor
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Bipolar transistor.
MMSZ11SOD-123Zener diode, 2 pins, onsemiZener diodeSOD-1232 pinsonsemi
- What it is
- Zener diode
- Maker
- onsemi
- Package
- SOD-123
- Pins
- 2
- Details
- Zener Voltage Regulators MMSZxxxT1G Series, SZMMSZxxxT1G Series
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
NZ8F20VMX2WSOD-882Zener diode, 2 pins, onsemiZener diodeSOD-8822 pinsonsemi
- What it is
- Zener diode
- Maker
- onsemi
- Package
- SOD-882
- Pins
- 2
- Details
- Zener Diode Voltage Regulators NZ8F Series
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
PTVS5V0S1UR-MSSOD-123FTVS diode, 2 pins, MSKSEMITVS diodeSOD-123F2 pinsMSKSEMI
- What it is
- TVS diode
- Maker
- MSKSEMI
- Package
- SOD-123F
- Pins
- 2
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
PZ2FD2V7HASOD-882Zener diode, 2 pins, PrisemiZener diodeSOD-8822 pinsPrisemi
- What it is
- Zener diode
- Maker
- Prisemi
- Package
- SOD-882
- Pins
- 2
- Details
- Zener diode, 2.65 V, 1 V
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
S-LBZT52B5V1T1GSOD-123Zener diode, 2 pins, LRCZener diodeSOD-1232 pinsLRC
- What it is
- Zener diode
- Maker
- LRC
- Package
- SOD-123
- Pins
- 2
- Details
- Zener diode, VZ Min 4.98 V, VZ Nom 5.1 V, VZ Max 5.2 V
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
S-LBZX84B5V1LT1GSOT-23Zener diode, 3 pins, LRCZener diodeSOT-233 pinsLRC
- What it is
- Zener diode
- Maker
- LRC
- Package
- SOT-23
- Pins
- 3
- Details
- Zener diode, VZ Min 4.98 V, VZ Nom 5.1 V, VZ Max 5.2 V
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
S-LEDZ5.1BT1GSOD-523Zener diode, 2 pins, LRCZener diodeSOD-5232 pinsLRC
- What it is
- Zener diode
- Maker
- LRC
- Package
- SOD-523
- Pins
- 2
- Details
- Zener diode, VZ Min 4.98 V, VZ Nom 5.1 V, VZ Max 5.2 V
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
S-LEDZ5.1BT1G-SSOD-523Zener diode, 2 pins, LRCZener diodeSOD-5232 pinsLRC
- What it is
- Zener diode
- Maker
- LRC
- Package
- SOD-523
- Pins
- 2
- Details
- Zener diode, VZ Min 4.98 V, VZ Nom 5.1 V, VZ Max 5.2 V
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
S-LMBT3906DW1T1GSOT-363PNP transistor, 6 pins, LRCPNP transistorSOT-3636 pinsLRC
- What it is
- PNP transistor
- Maker
- LRC
- Package
- SOT-363
- Pins
- 6
- Details
- Bipolar transistor, PNP, IC 200 mA, VCEO 40 V
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: PNP transistor.
3 more parts have no package on record
NCP114AMX092LDO regulator, onsemiLDO regulatorNot recordedNot recordedonsemi
- What it is
- LDO regulator
- Maker
- onsemi
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Voltage Regulator - CMOS Low Dropout
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Voltage regulator.
NCP706MX295LDO regulator, onsemiLDO regulatorNot recordedNot recordedonsemi
- What it is
- LDO regulator
- Maker
- onsemi
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 1 A, 1% Precision Very Low Dropout Voltage Regulator with Enable
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Voltage regulator.
PESD5V0L5UFUMWNot recordedNot recordedNot recordedUMW
- What it is
- Not recorded
- Maker
- UMW
- Package
- Not recorded
- Pins
- Not recorded
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: This part.
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.
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.
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.
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.
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.
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