SMD code AOs
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.
The last letter, s, is lower case, which on NXP and Philips parts is a date or factory code, so it was set aside and AO was searched.
31 parts are printed AOs
Not sure which one you have?
Answer up to 4 quick questions and these 31 parts are ranked, with a meter test that settles it. It works on a dead part too.
2SA1980E-OSOT-523PNP transistor, 3 pins, AUK SemiconductorPNP transistorSOT-5233 pinsAUK Semiconductor
- What it is
- PNP transistor
- Maker
- AUK Semiconductor
- Package
- SOT-523
- Pins
- 3
- Details
- PNP transistor: GP, 50V, 150mA, 150mW, B=70..140, 80MHz
- Source
- Published code list
Is it dead? The meter test is below: PNP transistor.
2SC2880-OSOT-89NPN transistor, 3 pins, ToshibaNPN transistorSOT-893 pinsToshiba
- What it is
- NPN transistor
- Maker
- Toshiba
- Package
- SOT-89
- Pins
- 3
- Details
- Si-npn: HV, 150V, 50mA, 500mW, B=70..140, 120MHz
- Source
- Published code list
Is it dead? The meter test is below: NPN transistor.
2SC2880OSOT-893 pins, ToshibaNot recordedSOT-893 pinsToshiba
- What it is
- Not recorded
- Maker
- Toshiba
- Package
- SOT-89
- Pins
- 3
- Source
- Published code list
Is it dead? The meter test is below: This part.
2SC4210-OSOT-23NPN transistor, 3 pins, ToshibaNPN transistorSOT-233 pinsToshiba
- What it is
- NPN transistor
- Maker
- Toshiba
- Package
- SOT-23
- Pins
- 3
- Details
- NPN transistor: AF, 35V, 800mA, 200mW, B=100..200, 120MHz
- Source
- Published code list
Is it dead? The meter test is below: NPN transistor.
2SC4210OSOT-233 pins, ToshibaNot recordedSOT-233 pinsToshiba
- What it is
- Not recorded
- Maker
- Toshiba
- Package
- SOT-23
- Pins
- 3
- Source
- Published code list
Is it dead? The meter test is below: This part.
BCW60ARSOT-233 pins, ITTNot recordedSOT-233 pinsITT
- What it is
- Not recorded
- Maker
- ITT
- Package
- SOT-23
- Pins
- 3
- Details
- Si-npn: GP, 32V, 0.2A, 250MHz, B=120..220
- Source
- Published code list
Is it dead? The meter test is below: This part.
FSSH110SMASchottky diode, 2 pins, Fagor ElectronicaSchottky diodeSMA2 pinsFagor Electronica
- What it is
- Schottky diode
- Maker
- Fagor Electronica
- Package
- SMA
- Pins
- 2
- Details
- Diode: SBR, 110V, 1A, Vf<0.8V(1A)
- Source
- Published code list
Is it dead? The meter test is below: Schottky diode.
GS6333UR19D1SOT-23Voltage supervisor, 3 pins, VishayVoltage supervisorSOT-233 pinsVishay
- What it is
- Voltage supervisor
- Maker
- Vishay
- Package
- SOT-23
- Pins
- 3
- Details
- CMOS-IC: Voltage Detector 1,9V, -Reset Push-pull output, 1,5ms
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
IMP811JEUS-TSOT-1434 pins, IMPNot recordedSOT-1434 pinsIMP
- What it is
- Not recorded
- Maker
- IMP
- Package
- SOT-143
- Pins
- 4
- Details
- CMOS-IC: Voltage Detector 4V, MR, -Reset ODO, 140ms
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
ISL60002CIH312ZSOT-23Voltage reference, 3 pins, IntersilVoltage referenceSOT-233 pinsIntersil
- What it is
- Voltage reference
- Maker
- Intersil
- Package
- SOT-23
- Pins
- 3
- Details
- Voltage reference IC: High precision, 1.250V±2.5mV
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
KTC4372-OSOT-89NPN transistor, 3 pins, KECNPN transistorSOT-893 pinsKEC
- What it is
- NPN transistor
- Maker
- KEC
- Package
- SOT-89
- Pins
- 3
- Details
- Si-npn: HV, Sw, 150V, 50mA, 500mW, B=70..140, 120MHz
- Source
- Published code list
Is it dead? The meter test is below: NPN transistor.
4 more parts have no package on record
BZX884B6V2LZener diode, VishayZener diodeNot recordedNot recordedVishay
- What it is
- Zener diode
- Maker
- Vishay
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 6.2 V Zener diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
2SA1980EF-OPNP transistor, AUK SemiconductorPNP transistorNot recordedNot recordedAUK Semiconductor
- What it is
- PNP transistor
- Maker
- AUK Semiconductor
- Package
- Not recorded
- Pins
- Not recorded
- Details
- PNP transistor: GP, 50V, 150mA, 150mW, B=70..140, 80MHz
- Source
- Published code list
Is it dead? The meter test is below: PNP transistor.
BFP4905 pins, InfineonNot recordedNot recorded5 pinsInfineon
- What it is
- Not recorded
- Maker
- Infineon
- Package
- Not recorded
- Pins
- 5
- Source
- Published code list
Is it dead? The meter test is below: This part.
MA5Z300-HZener diode, PanasonicZener diodeNot recordedNot recordedPanasonic
- What it is
- Zener diode
- Maker
- Panasonic
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Zener diode: 300V, Iz=0.1mA, 150mW
- Source
- Published code list
Is it dead? The meter test is below: Zener 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.
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.
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.
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.
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.
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.
Printed with a code easy to misread as AOs
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 142 more parts.
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