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.
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.
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.
LDK320ADU120RSOT-89LDO regulator, 3 pins, STMicroelectronicsLDO regulatorSOT-893 pinsSTMicroelectronics
- What it is
- LDO regulator
- Maker
- STMicroelectronics
- Package
- SOT-89
- Pins
- 3
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Voltage regulator.
LEDZ5.1BPT1GSOD-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.
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.
LMBT3906DW1T1GSOT-363Transistor, 6 pins, LRCTransistorSOT-3636 pinsLRC
- What it is
- Transistor
- Maker
- LRC
- Package
- SOT-363
- Pins
- 6
- Details
- Bipolar transistor, Dual P, IC 200 mA, VCEO 40 V
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Bipolar transistor.
LSI1012BN3T5GSOT-883N-channel MOSFET, 3 pins, LRCN-channel MOSFETSOT-8833 pinsLRC
- What it is
- N-channel MOSFET
- Maker
- LRC
- Package
- SOT-883
- Pins
- 3
- Details
- MOSFET, N-Channel(with ESD), VDSS 20 V, VGS 10 V
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: N-channel MOSFET.
LUDZS5.1BPT1GSOD-323Zener diode, 2 pins, LRCZener diodeSOD-3232 pinsLRC
- What it is
- Zener diode
- Maker
- LRC
- Package
- SOD-323
- 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.
LUDZS5.1BT1GSOD-323Zener diode, 2 pins, LRCZener diodeSOD-3232 pinsLRC
- What it is
- Zener diode
- Maker
- LRC
- Package
- SOD-323
- 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.
MM3Z9V1BWSOD-323Zener diode, 2 pins, YFWZener diodeSOD-3232 pinsYFW
- What it is
- Zener diode
- Maker
- YFW
- Package
- SOD-323
- Pins
- 2
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
MMBD914SOT-23Switching diode, 3 pins, Diodes IncorporatedSwitching diodeSOT-233 pinsDiodes Incorporated
- What it is
- Switching diode
- Maker
- Diodes Incorporated
- Package
- SOT-23
- Pins
- 3
- Details
- Surface-mount fast switching diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
MMBD4148SOT-23Switching diode, 3 pins, Taitron ComponentsSwitching diodeSOT-233 pinsTaitron Components
- What it is
- Switching diode
- Maker
- Taitron Components
- Package
- SOT-23
- Pins
- 3
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
MMBD4148-AUSOT-23Switching diode, 3 pins, PanjitSwitching diodeSOT-233 pinsPanjit
- What it is
- Switching diode
- Maker
- Panjit
- Package
- SOT-23
- Pins
- 3
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
MMBD4148TSSOD-523Switching diode, 2 pins, PanjitSwitching diodeSOD-5232 pinsPanjit
- What it is
- Switching diode
- Maker
- Panjit
- Package
- SOD-523
- Pins
- 2
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
MMBD4148TS-AUSOD-523Switching diode, 2 pins, PanjitSwitching diodeSOD-5232 pinsPanjit
- What it is
- Switching diode
- Maker
- Panjit
- Package
- SOD-523
- Pins
- 2
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon 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.
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.
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.
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.
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.
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