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.
RB520L-30SOD-882Schottky diode, 2 pins, Galaxy MicroelectronicsSchottky diodeSOD-8822 pinsGalaxy Microelectronics
- What it is
- Schottky diode
- Maker
- Galaxy Microelectronics
- Package
- SOD-882
- Pins
- 2
- Details
- 0.2A, 30V, Surface Mount Small Signal Schottky Diodes
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
RB520S-30SOD-523Schottky diode, 2 pins, Taiwan SemiconductorSchottky diodeSOD-5232 pinsTaiwan Semiconductor
- What it is
- Schottky diode
- Maker
- Taiwan Semiconductor
- Package
- SOD-523
- Pins
- 2
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
RB520SM-30SOD-523Schottky diode, 2 pins, ROHMSchottky diodeSOD-5232 pinsROHM
- What it is
- Schottky diode
- Maker
- ROHM
- Package
- SOD-523
- Pins
- 2
- Details
- Schottky Barrier Diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
RB520SM-30FHSOD-523Schottky diode, 2 pins, ROHMSchottky diodeSOD-5232 pinsROHM
- What it is
- Schottky diode
- Maker
- ROHM
- Package
- SOD-523
- Pins
- 2
- Details
- Schottky Barrier Diode (AEC-Q101 qualified)
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
RB520V-30SOD-323Schottky diode, 2 pins, Galaxy MicroelectronicsSchottky diodeSOD-3232 pinsGalaxy Microelectronics
- What it is
- Schottky diode
- Maker
- Galaxy Microelectronics
- Package
- SOD-323
- Pins
- 2
- Details
- 0.2A, 30V, Surface Mount Small Signal Schottky Diodes
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
RB551VM-40SOD-323Schottky diode, 2 pins, ROHMSchottky diodeSOD-3232 pinsROHM
- What it is
- Schottky diode
- Maker
- ROHM
- Package
- SOD-323
- Pins
- 2
- Details
- Schottky Barrier Diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
RSAC6.8CMSOD-923ESD protection diode, 2 pins, ROHMESD protection diodeSOD-9232 pinsROHM
- What it is
- ESD protection diode
- Maker
- ROHM
- Package
- SOD-923
- Pins
- 2
- Details
- Transient Voltage Suppressor
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
S-L1SS356T1GSOD-323Switching diode, 2 pins, LRCSwitching diodeSOD-3232 pinsLRC
- What it is
- Switching diode
- Maker
- LRC
- Package
- SOD-323
- Pins
- 2
- Details
- Switching diode, VR 35 V, IF 100 mA, VF Max 1 V
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
S-LBTN180TZLGSOT-89NPN transistor, 3 pins, LRCNPN transistorSOT-893 pinsLRC
- What it is
- NPN transistor
- Maker
- LRC
- Package
- SOT-89
- Pins
- 3
- Details
- Bipolar transistor, NPN, IC 1000 mA, VCEO 80 V
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: NPN transistor.
S-LBTN180Y3T1GSOT-89NPN transistor, 3 pins, LRCNPN transistorSOT-893 pinsLRC
- What it is
- NPN transistor
- Maker
- LRC
- Package
- SOT-89
- Pins
- 3
- Details
- Bipolar transistor, NPN, IC 1000 mA, VCEO 80 V
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: NPN transistor.
S-LBTN180Y3T1G-SSOT-89NPN transistor, 3 pins, LRCNPN transistorSOT-893 pinsLRC
- What it is
- NPN transistor
- Maker
- LRC
- Package
- SOT-89
- Pins
- 3
- Details
- Bipolar transistor, NPN, IC 1000 mA, VCEO 80 V
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: NPN transistor.
SCS388S-CSOD-523Switching diode, 2 pins, SeCoSSwitching diodeSOD-5232 pinsSeCoS
- What it is
- Switching diode
- Maker
- SeCoS
- Package
- SOD-523
- Pins
- 2
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
3 more parts have no package on record
RB520SSchottky diode, Formosa MicrosemiSchottky diodeNot recordedNot recordedFormosa Microsemi
- What it is
- Schottky diode
- Maker
- Formosa Microsemi
- Package
- Not recorded
- Pins
- Not recorded
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
S-LESD08LL5.0CT5GESD protection diode, LRCESD protection diodeNot recordedNot recordedLRC
- What it is
- ESD protection diode
- Maker
- LRC
- Package
- Not recorded
- Pins
- Not recorded
- Details
- ESD protection diode, VRWM 5 V, IR @VRWM 0.05 μA, VBR Min 7 V
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
S-LSI1013XT1GP-channel MOSFET, LRCP-channel MOSFETNot recordedNot recordedLRC
- What it is
- P-channel MOSFET
- Maker
- LRC
- Package
- Not recorded
- Pins
- Not recorded
- Details
- MOSFET, P-Channel(with ESD), VDSS 20 V, VGS 6 V
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: P-channel MOSFET.
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.
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.
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.
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.
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.
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.
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