SMD code BDs
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 BD was searched.
136 parts are printed BDs
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.
ABCP54-16-HFSOT-223NPN transistor, 4 pins, ComchipNPN transistorSOT-2234 pinsComchip
- What it is
- NPN transistor
- Maker
- Comchip
- Package
- SOT-223
- Pins
- 4
- Details
- 45 V, 1 A NPN transistor
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: NPN transistor.
ABCX54-16-HFSOT-89NPN transistor, 3 pins, ComchipNPN transistorSOT-893 pinsComchip
- What it is
- NPN transistor
- Maker
- Comchip
- Package
- SOT-89
- Pins
- 3
- Details
- 45 V, 1 A NPN transistor
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: NPN transistor.
BCP54SOT-223NPN transistor, 4 pins, Galaxy MicroelectronicsNPN transistorSOT-2234 pinsGalaxy Microelectronics
- What it is
- NPN transistor
- Maker
- Galaxy Microelectronics
- Package
- SOT-223
- Pins
- 4
- Details
- 45V, 1A, General Purpose NPN Bipolar Transistor
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: NPN transistor.
BCP54-16-HFSOT-223NPN transistor, 4 pins, ComchipNPN transistorSOT-2234 pinsComchip
- What it is
- NPN transistor
- Maker
- Comchip
- Package
- SOT-223
- Pins
- 4
- Details
- 45 V, 1 A NPN transistor
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: NPN transistor.
BCW61DSOT-23PNP transistor, 3 pins, InfineonPNP transistorSOT-233 pinsInfineon
- What it is
- PNP transistor
- Maker
- Infineon
- Package
- SOT-23
- Pins
- 3
- Details
- Bipolar transistor, 45 V, 0.1 A
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: PNP transistor.
BCX54-16SOT-89NPN transistor, 3 pins, InfineonNPN transistorSOT-893 pinsInfineon
- What it is
- NPN transistor
- Maker
- Infineon
- Package
- SOT-89
- Pins
- 3
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: NPN transistor.
BZT52H-C6V2SOD-123FZener diode, 2 pins, NexperiaZener diodeSOD-123F2 pinsNexperia
- What it is
- Zener diode
- Maker
- Nexperia
- Package
- SOD-123F
- Pins
- 2
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
CDBF42-HFSOD-323Schottky diode, 2 pins, ComchipSchottky diodeSOD-3232 pinsComchip
- What it is
- Schottky diode
- Maker
- Comchip
- Package
- SOD-323
- Pins
- 2
- Details
- 30 V, 0.2 A Schottky barrier diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
7 more parts have no package on record
ACDBQC42-HFSchottky diode, ComchipSchottky diodeNot recordedNot recordedComchip
- What it is
- Schottky diode
- Maker
- Comchip
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 30 V, 0.2 A Schottky barrier diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
ACDBUC42-HFSchottky diode, ComchipSchottky diodeNot recordedNot recordedComchip
- What it is
- Schottky diode
- Maker
- Comchip
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 30 V, 0.2 A Schottky barrier diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
BZX884B24LZener diode, VishayZener diodeNot recordedNot recordedVishay
- What it is
- Zener diode
- Maker
- Vishay
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 24 V Zener diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
CDBQC42-HFSchottky diode, ComchipSchottky diodeNot recordedNot recordedComchip
- What it is
- Schottky diode
- Maker
- Comchip
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 30 V, 0.2 A Schottky barrier diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
CDBU42-HFSchottky diode, ComchipSchottky diodeNot recordedNot recordedComchip
- What it is
- Schottky diode
- Maker
- Comchip
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 30 V, 0.2 A Schottky barrier diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
CDBUR42-HFSchottky diode, ComchipSchottky diodeNot recordedNot recordedComchip
- What it is
- Schottky diode
- Maker
- Comchip
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 30 V, 0.2 A Schottky barrier diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
CDBVRL240A-HFSchottky diode, ComchipSchottky diodeNot recordedNot recordedComchip
- What it is
- Schottky diode
- Maker
- Comchip
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 40 V, 2 A Schottky barrier diode
- 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.
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.
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.
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.
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.
Printed with a code easy to misread as BDs
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 59 more parts.
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