SMD code XB in SOT-23
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.
11 parts in SOT-23 are printed XB
Not sure which one you have?
Answer up to 4 quick questions and these 28 parts are ranked, with a meter test that settles it. It works on a dead part too.
BCR553SOT-23Digital transistor (resistors built in), InfineonDigital transistor (resistors built in)Infineon
- What it is
- Digital transistor (resistors built in)
- Maker
- Infineon
- Package
- SOT-23
- Pins
- 3
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Digital transistor.
BZX84B56SOT-23Zener diode, Good-ArkZener diodeGood-Ark
- What it is
- Zener diode
- Maker
- Good-Ark
- Package
- SOT-23
- Pins
- 3
- Details
- Zener diode, VZ 56 V, 0.35 W
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
BZX84B56-CSOT-23Zener diode, SeCoSZener diodeSeCoS
- What it is
- Zener diode
- Maker
- SeCoS
- Package
- SOT-23
- Pins
- 3
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
BZX84B56-HFSOT-23Zener diode, ComchipZener diodeComchip
- What it is
- Zener diode
- Maker
- Comchip
- Package
- SOT-23
- Pins
- 3
- Details
- 56 V 0.35 mW zener diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
2SC4416SOT-23RenesasNot recordedRenesas
- What it is
- Not recorded
- Maker
- Renesas
- Package
- SOT-23
- Pins
- 3
- Details
- Si-npn: UHF/VHF, 25V, 50mA, 150mW, B=50..180, >3GHz
- Source
- Published code list
Is it dead? The meter test is below: This part.
2SJ557SOT-23RenesasNot recordedRenesas
- What it is
- Not recorded
- Maker
- Renesas
- Package
- SOT-23
- Pins
- 3
- Details
- p-MOS*-e: V-MOS, LogL, 30V, ±2,5A, <0,29Ω
- Source
- Published code list
Is it dead? The meter test is below: This part.
5LP01CSOT-23Sanyo ElectricNot recordedSanyo Electric
- What it is
- Not recorded
- Maker
- Sanyo Electric
- Package
- SOT-23
- Pins
- 3
- Details
- p-MOS*+Di: Sw, U-Hi-Sp, 50V, 70mA, 250mW, 20/250ns
- Source
- Published code list
Is it dead? The meter test is below: This part.
APX810-44SASOT-23Voltage supervisor, Diodes IncorporatedVoltage supervisorDiodes Incorporated
- What it is
- Voltage supervisor
- Maker
- Diodes Incorporated
- Package
- SOT-23
- Pins
- 3
- Details
- Voltage detector IC: 4.38V±1.5%, +Reset PPO
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
APX810S-44SA-7SOT-23Voltage supervisor, Diodes IncorporatedVoltage supervisorDiodes Incorporated
- What it is
- Voltage supervisor
- Maker
- Diodes Incorporated
- Package
- SOT-23
- Pins
- 3
- Details
- Voltage detector IC: 4.38V±1.5%, +Reset PPO, Rdt=240ms
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
BZX99-C5V1SOT-23NexperiaNot recordedNexperia
- What it is
- Not recorded
- Maker
- Nexperia
- Package
- SOT-23
- Pins
- 3
- Details
- 5.1V 0.3W zener
- Source
- Published code list
Is it dead? The meter test is below: Zener diode.
RN1402SOT-23Digital transistor (NPN, resistors built in), ToshibaDigital transistor (NPN, resistors built in)Toshiba
- What it is
- Digital transistor (NPN, resistors built in)
- Maker
- Toshiba
- Package
- SOT-23
- Pins
- 3
- Details
- Si-npn-Digi: Sw, 50V, 100mA, 400mW, R1/R2=10k/10k
- Source
- Published code list
Is it dead? The meter test is below: Digital transistor.
4 more parts have no package on record. Nothing rules them out, so they stay.
ET51815YBLDO regulator, ETEKLDO regulatorETEK
- What it is
- LDO regulator
- Maker
- ETEK
- Package
- Not recorded
- Pins
- Not recorded
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Voltage regulator.
NX3P1108UKLoad switch, NXPLoad switchNXP
- What it is
- Load switch
- Maker
- NXP
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Logic controlled high-side power switch
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Load switch.
PBZ15BZener diode, ROHMZener diodeROHM
- What it is
- Zener diode
- Maker
- ROHM
- Package
- Not recorded
- Pins
- Not recorded
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
4A002MH5Sanyo ElectricNot recordedSanyo Electric
- What it is
- Not recorded
- Maker
- Sanyo Electric
- Package
- Not recorded
- Pins
- Not recorded
- Details
- CMOS logic IC: 2-input NOR gate
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
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.
Digital transistor
Ohms range, part lifted. The datasheet gives the built-in resistors: R1 in series with the base, R2 from base to emitter.
Working, it reads
Base to emitter reads about R1 plus R2 either way round, about 20 kΩ on a 10 k and 10 k part, give or take their wide tolerance. Collector to emitter reads open. A part with no R2 reads a junction behind R1 one way instead.
Dead, it reads
- Collector to emitter the same both ways, near 0 Ω with a continuous beep: shorted.
- From the base, open or far above R1 plus R2: R1 has failed. Static damage shows here most often.
- Base to emitter near 0 Ω: failed short.
- 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:
- The readings depend on the resistor values, so an identical part elsewhere on the board is the surest reference. Measure it the same way.
- Watch for:
- On the diode range a good part with 10 kΩ resistors reads open on every pair, so a good part looks dead there. Use the ohms range.
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.
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.
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.
Digital transistor
Ohms range, part lifted. The datasheet gives the built-in resistors: R1 in series with the base, R2 from base to emitter.
Working, it reads
Base to emitter reads about R1 plus R2 either way round, about 20 kΩ on a 10 k and 10 k part, give or take their wide tolerance. Collector to emitter reads open. A part with no R2 reads a junction behind R1 one way instead.
Dead, it reads
- Collector to emitter the same both ways, near 0 Ω with a continuous beep: shorted.
- From the base, open or far above R1 plus R2: R1 has failed. Static damage shows here most often.
- Base to emitter near 0 Ω: failed short.
- 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:
- The readings depend on the resistor values, so an identical part elsewhere on the board is the surest reference. Measure it the same way.
- Watch for:
- On the diode range a good part with 10 kΩ resistors reads open on every pair, so a good part looks dead there. Use the ohms range.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
Voltage regulator
Voltage, board powered, black probe on ground. Then ohms with the power off.
Working, it reads
Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.
Dead, it reads
- Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
- Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
- Power off, input to output near 0 Ω: shorted.
- On the board:
- An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
- Compare:
- The same regulator on another rail or another board shows the right voltages and the right resistances.
- Watch for:
- Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.
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.
Printed with a code easy to misread as XB
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 XB
For a marking with its end worn or burnt off. Each code has a page of its own.
Codes not listed here are printed on 31 more parts.
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