SMD code B-
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.
152 parts are printed B-
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.
2SB766ASOT-89PNP transistor, 3 pins, SeCoSPNP transistorSOT-893 pinsSeCoS
- What it is
- PNP transistor
- Maker
- SeCoS
- Package
- SOT-89
- Pins
- 3
- Details
- PNP bipolar transistor
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: PNP transistor.
AMP01EA045SOD-123FSchottky diode, 2 pins, ShindengenSchottky diodeSOD-123F2 pinsShindengen
- What it is
- Schottky diode
- Maker
- Shindengen
- Package
- SOD-123F
- Pins
- 2
- Details
- Schottky Barrier Diodes 45V, 1A
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
AP5N2K2EN1SOT-723N-channel MOSFET, 3 pins, Advanced Power ElectronicsN-channel MOSFETSOT-7233 pinsAdvanced Power Electronics
- What it is
- N-channel MOSFET
- Maker
- Advanced Power Electronics
- Package
- SOT-723
- Pins
- 3
- Details
- 50 V, 0.2 A N-channel MOSFET
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: N-channel MOSFET.
APL3537BWLCSPLoad switch, AnpecLoad switchWLCSPNot recordedAnpec
- What it is
- Load switch
- Maker
- Anpec
- Package
- WLCSP
- Pins
- Not recorded
- Details
- Ultra-Low On-Resistance, Power Load Switch With Soft Start
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Load switch.
ARB520S-30-HFSOD-523Schottky diode, 2 pins, ComchipSchottky diodeSOD-5232 pinsComchip
- What it is
- Schottky diode
- Maker
- Comchip
- Package
- SOD-523
- Pins
- 2
- Details
- 30 V, 0.2 A Schottky barrier diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
BAS16-03WSOD-323Switching diode, 2 pins, InfineonSwitching diodeSOD-3232 pinsInfineon
- What it is
- Switching diode
- Maker
- Infineon
- Package
- SOD-323
- Pins
- 2
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
9 more parts have no package on record
AON1606MOSFET, Alpha & Omega SemiconductorMOSFETNot recordedNot recordedAlpha & Omega Semiconductor
- What it is
- MOSFET
- Maker
- Alpha & Omega Semiconductor
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Low-voltage (12-30 V) MOSFET
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: MOSFET.
AON1606LMOSFET, Alpha & Omega SemiconductorMOSFETNot recordedNot recordedAlpha & Omega Semiconductor
- What it is
- MOSFET
- Maker
- Alpha & Omega Semiconductor
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Low-voltage (12-30 V) MOSFET
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: MOSFET.
AOZ8S204BLS-03ESD protection diode, Alpha & Omega SemiconductorESD protection diodeNot recordedNot recordedAlpha & Omega Semiconductor
- What it is
- ESD protection diode
- Maker
- Alpha & Omega Semiconductor
- Package
- Not recorded
- Pins
- Not recorded
- Details
- ESD protection for high-speed interfaces
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
AOZ8S204BLS-05ESD protection diode, Alpha & Omega SemiconductorESD protection diodeNot recordedNot recordedAlpha & Omega Semiconductor
- What it is
- ESD protection diode
- Maker
- Alpha & Omega Semiconductor
- Package
- Not recorded
- Pins
- Not recorded
- Details
- ESD protection for high-speed interfaces
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
AOZ8S322UD2-03ESD protection diode, Alpha & Omega SemiconductorESD protection diodeNot recordedNot recordedAlpha & Omega Semiconductor
- What it is
- ESD protection diode
- Maker
- Alpha & Omega Semiconductor
- Package
- Not recorded
- Pins
- Not recorded
- Details
- ESD protection for high-speed interfaces
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
AOZ8829ADI-05ESD protection diode, Alpha & Omega SemiconductorESD protection diodeNot recordedNot recordedAlpha & Omega Semiconductor
- What it is
- ESD protection diode
- Maker
- Alpha & Omega Semiconductor
- Package
- Not recorded
- Pins
- Not recorded
- Details
- ESD protection for high-speed interfaces
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
APL3233BBattery protection IC, AnpecBattery protection ICNot recordedNot recordedAnpec
- What it is
- Battery protection IC
- Maker
- Anpec
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Li+ Charger Protection IC
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Integrated circuit.
APW7582BDC-DC converter, AnpecDC-DC converterNot recordedNot recordedAnpec
- What it is
- DC-DC converter
- Maker
- Anpec
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 0.6A, 5V Input, Low IQ Buck Converter
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Integrated circuit.
BAT15-098LRHSchottky diode, InfineonSchottky diodeNot recordedNot recordedInfineon
- What it is
- Schottky diode
- Maker
- Infineon
- Package
- Not recorded
- Pins
- Not recorded
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky 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.
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.
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.
MOSFET
Diode range, part lifted. Test drain to source first, then short gate to source and test again.
Working, it reads
One way between drain and source reads about 0.4 to 0.9 V, the body diode, and the other way open. The gate reads open to both other pins.
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.
- No body diode at all: failed open.
- On the board
- the gate usually has a resistor to the source, which reads as that resistor and 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.
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.
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.
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.
Load switch
Voltage, board powered, black probe on ground.
Working, it reads
Switched on, the output pin sits at the input voltage. Switched off, it sits near 0 V.
Dead, it reads
- Output at the input voltage while switched off: the pass element has shorted.
- Input present and switched on, no output: failed open, or shut down into a shorted load. Power off and measure output to ground.
- On the board:
- An output near 0 Ω to ground is usually the load. Lift the output pin to see which.
- 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 pinout and whether the enable is active high or low differ between parts. The datasheet gives both.
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.
Printed with a code easy to misread as B-
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 3 more parts.
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