SMD code A0-
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.
92 parts are printed A0-
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.
BZX7B22SOD-723Zener diode, 2 pins, Good-ArkZener diodeSOD-7232 pinsGood-Ark
- What it is
- Zener diode
- Maker
- Good-Ark
- Package
- SOD-723
- Pins
- 2
- Details
- Zener diode, VZ 22 V, 0.1 W
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
BZX84-C43,215SOT-23Zener diode, 3 pins, HXYZener diodeSOT-233 pinsHXY
- What it is
- Zener diode
- Maker
- HXY
- Package
- SOT-23
- Pins
- 3
- Details
- Zener diode, 75 V, 0.05 A
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
BZX84C43SOT-23Zener diode, 3 pins, DiotecZener diodeSOT-233 pinsDiotec
- What it is
- Zener diode
- Maker
- Diotec
- Package
- SOT-23
- Pins
- 3
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
BZX84C43-Q1SOT-23Zener diode, 3 pins, Formosa MicrosemiZener diodeSOT-233 pinsFormosa Microsemi
- What it is
- Zener diode
- Maker
- Formosa Microsemi
- Package
- SOT-23
- Pins
- 3
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
1N5817WBSOD-123FSchottky diode, 2 pins, Semtech ElectronicsSchottky diodeSOD-123F2 pinsSemtech Electronics
- What it is
- Schottky diode
- Maker
- Semtech Electronics
- Package
- SOD-123F
- Pins
- 2
- Details
- Diode: SBR, 20V, 1A, Vf<0.45V(1A), 120pF
- Source
- Published code list
Is it dead? The meter test is below: Schottky diode.
AO3400SOT-23N-channel MOSFET, 3 pins, AlphaN-channel MOSFETSOT-233 pinsAlpha
- What it is
- N-channel MOSFET
- Maker
- Alpha
- Package
- SOT-23
- Pins
- 3
- Details
- N-channel MOSFET, 30 V
- Source
- Published code list
Is it dead? The meter test is below: N-channel MOSFET.
BL8555-20AQSOT-353LDO regulator, 5 pins, Shanghai BellingLDO regulatorSOT-3535 pinsShanghai Belling
- What it is
- LDO regulator
- Maker
- Shanghai Belling
- Package
- SOT-353
- Pins
- 5
- Details
- Linear voltage regulator IC: LDO, 2.0V±2%, 50mA, +CE
- Source
- Published code list
Is it dead? The meter test is below: Voltage regulator.
BL8555-20ARASOT-23-5LDO regulator, 5 pins, Shanghai BellingLDO regulatorSOT-23-55 pinsShanghai Belling
- What it is
- LDO regulator
- Maker
- Shanghai Belling
- Package
- SOT-23-5
- Pins
- 5
- Details
- Linear voltage regulator IC: LDO, 2.0V±2%, 50mA, +CE
- Source
- Published code list
Is it dead? The meter test is below: Voltage regulator.
BL8555-20ARBSOT-23-5LDO regulator, 5 pins, Shanghai BellingLDO regulatorSOT-23-55 pinsShanghai Belling
- What it is
- LDO regulator
- Maker
- Shanghai Belling
- Package
- SOT-23-5
- Pins
- 5
- Details
- Linear voltage regulator IC: LDO, 2.0V±2%, 50mA, +CE
- Source
- Published code list
Is it dead? The meter test is below: Voltage regulator.
BL8555-20KQSOT-353LDO regulator, 5 pins, Shanghai BellingLDO regulatorSOT-3535 pinsShanghai Belling
- What it is
- LDO regulator
- Maker
- Shanghai Belling
- Package
- SOT-353
- Pins
- 5
- Details
- Linear voltage regulator IC: LDO, 2.0V±2%, 50mA
- Source
- Published code list
Is it dead? The meter test is below: Voltage regulator.
BL8555-20KRASOT-23-5LDO regulator, 5 pins, Shanghai BellingLDO regulatorSOT-23-55 pinsShanghai Belling
- What it is
- LDO regulator
- Maker
- Shanghai Belling
- Package
- SOT-23-5
- Pins
- 5
- Details
- Linear voltage regulator IC: LDO, 2.0V±2%, 50mA
- Source
- Published code list
Is it dead? The meter test is below: Voltage regulator.
BL8555-20KRBSOT-23-5LDO regulator, 5 pins, Shanghai BellingLDO regulatorSOT-23-55 pinsShanghai Belling
- What it is
- LDO regulator
- Maker
- Shanghai Belling
- Package
- SOT-23-5
- Pins
- 5
- Details
- Linear voltage regulator IC: LDO, 2.0V±2%, 50mA
- Source
- Published code list
Is it dead? The meter test is below: Voltage regulator.
BL8555-30AQSOT-353LDO regulator, 5 pins, Shanghai BellingLDO regulatorSOT-3535 pinsShanghai Belling
- What it is
- LDO regulator
- Maker
- Shanghai Belling
- Package
- SOT-353
- Pins
- 5
- Details
- Linear voltage regulator IC: LDO, 3.0V±2%, 50mA, +CE
- Source
- Published code list
Is it dead? The meter test is below: Voltage regulator.
BL8555-30ARASOT-23-5LDO regulator, 5 pins, Shanghai BellingLDO regulatorSOT-23-55 pinsShanghai Belling
- What it is
- LDO regulator
- Maker
- Shanghai Belling
- Package
- SOT-23-5
- Pins
- 5
- Details
- Linear voltage regulator IC: LDO, 3.0V±2%, 50mA, +CE
- Source
- Published code list
Is it dead? The meter test is below: Voltage regulator.
1 more part has no package on record
ADA4075-2ACPZ-R78 pins, Analog DevicesNot recordedNot 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.
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.
Schottky diode
Diode range, part lifted or one leg off the pad. Red probe on the anode.
Working, it reads
About 0.15 to 0.45 V anode to cathode, roughly half a silicon diode, and open the other way.
Dead, it reads
- The same reading both ways round, near 0 V with a continuous beep or the same middling value: shorted.
- A reading the wrong way round as well: leaky.
- Open both ways: failed open.
- 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 large Schottky can read about 0.1 V forward and beep like a short, and leaks a little the wrong way when good, more when warm. It is shorted only if it reads the same both ways. Measure it cold, beside an identical cold one.
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.
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.
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.
Printed with a code easy to misread as A0-
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 12 more parts.
Did you find your part?
Open this in the search to correct a character or try another package.