SMD code AS
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.
9 parts are printed AS
Not sure which one you have?
Answer up to 4 quick questions and these 9 parts are ranked, with a meter test that settles it. It works on a dead part too.
AO3423SOT-23P-channel MOSFET, 3 pins, Alpha & Omega SemiconductorP-channel MOSFETSOT-233 pinsAlpha & Omega Semiconductor
- What it is
- P-channel MOSFET
- Maker
- Alpha & Omega Semiconductor
- Package
- SOT-23
- Pins
- 3
- Details
- P-channel MOSFET (8-60 V)
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: P-channel MOSFET.
AO3423LSOT-23P-channel MOSFET, 3 pins, Alpha & Omega SemiconductorP-channel MOSFETSOT-233 pinsAlpha & Omega Semiconductor
- What it is
- P-channel MOSFET
- Maker
- Alpha & Omega Semiconductor
- Package
- SOT-23
- Pins
- 3
- Details
- P-channel MOSFET (8-60 V)
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: P-channel MOSFET.
BAV19WSOD-123Switching diode, 2 pins, VishaySwitching diodeSOD-1232 pinsVishay
- What it is
- Switching diode
- Maker
- Vishay
- Package
- SOD-123
- Pins
- 2
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: Silicon diode.
BAV19W-GSOD-123Switching diode, 2 pins, VishaySwitching diodeSOD-1232 pinsVishay
- What it is
- Switching diode
- Maker
- Vishay
- Package
- SOD-123
- Pins
- 2
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: Silicon diode.
PJGBLC15SOD-323ESD protection diode, 2 pins, PanjitESD protection diodeSOD-3232 pinsPanjit
- What it is
- ESD protection diode
- Maker
- Panjit
- Package
- SOD-323
- Pins
- 2
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
PJGBLC15-AUSOD-323ESD protection diode, 2 pins, PanjitESD protection diodeSOD-3232 pinsPanjit
- What it is
- ESD protection diode
- Maker
- Panjit
- Package
- SOD-323
- Pins
- 2
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
3 more parts have no package on record
BAT18-05Schottky diode, InfineonSchottky diodeNot recordedNot recordedInfineon
- What it is
- Schottky diode
- Maker
- Infineon
- Package
- Not recorded
- Pins
- Not recorded
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: Schottky diode.
BZX884B7V5LZener diode, VishayZener diodeNot recordedNot recordedVishay
- What it is
- Zener diode
- Maker
- Vishay
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 7.5 V Zener diode
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: Zener diode.
VESD05A6-HAFESD protection diode, VishayESD protection diodeNot recordedNot recordedVishay
- What it is
- ESD protection diode
- Maker
- Vishay
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 6-Line ESD Protection Diode Array in LLP75
- 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.
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.
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.
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.
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.
Printed with a code easy to misread as AS
One character differs, and it is one that is easy to confuse under a lamp. Each code has a page of its own.
Codes that begin with AS
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.