SMD code MB in SOT-323
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.
3 parts in SOT-323 are printed MB
Not sure which one you have?
Answer up to 4 quick questions and these 23 parts are ranked, with a meter test that settles it. It works on a dead part too.
BAS70WAGPSOT-323Schottky diode, ChenmkoSchottky diodeChenmko
- What it is
- Schottky diode
- Maker
- Chenmko
- Package
- SOT-323
- Pins
- 3
- Details
- SCHOTTKY DIODE, 70 V, 70 mA
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
2SC5108-OSOT-323ToshibaNot recordedToshiba
- What it is
- Not recorded
- Maker
- Toshiba
- Package
- SOT-323
- Pins
- 3
- Details
- Si-npn: VHF/UHF-VCO, 20V, 30mA, 100mW, 6GHz, B=80..160
- Source
- Published code list
Is it dead? The meter test is below: This part.
PT7M6238CHC3ESOT-323Voltage supervisor, Pericom TechnologyVoltage supervisorPericom Technology
- What it is
- Voltage supervisor
- Maker
- Pericom Technology
- Package
- SOT-323
- Pins
- 3
- Details
- Voltage detector IC: 3.8V±1.5%, +Reset PPO, L-free
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
12 more parts have no package on record. Nothing rules them out, so they stay.
2SAR512RPNP transistor, ROHMPNP transistorROHM
- What it is
- PNP transistor
- Maker
- ROHM
- Package
- Not recorded
- Pins
- Not recorded
- Details
- PNP -2.0A -30V Middle Power Transistor
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: PNP transistor.
BGB420RF amplifier (MMIC), InfineonRF amplifier (MMIC)Infineon
- What it is
- RF amplifier (MMIC)
- Maker
- Infineon
- Package
- Not recorded
- Pins
- Not recorded
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: RF amplifier.
KTC812TNPN transistor, KECNPN transistorKEC
- What it is
- NPN transistor
- Maker
- KEC
- Package
- Not recorded
- Pins
- Not recorded
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: NPN transistor.
PBZ5.6BZener 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.
RB168VWM200Schottky diode, ROHMSchottky diodeROHM
- What it is
- Schottky diode
- Maker
- ROHM
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Schottky Barrier Diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
RB168VWM200TFSchottky diode, ROHMSchottky diodeROHM
- What it is
- Schottky diode
- Maker
- ROHM
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Schottky Barrier Diode (AEC-Q101 qualified)
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
74LVC1G02FX4Diodes IncorporatedNot recordedDiodes Incorporated
- What it is
- Not recorded
- Maker
- Diodes Incorporated
- 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.
BD49L36GVoltage supervisor, ROHMVoltage supervisorROHM
- What it is
- Voltage supervisor
- Maker
- ROHM
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Voltage Detector
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
BD52E26G-MVoltage supervisor, ROHMVoltage supervisorROHM
- What it is
- Voltage supervisor
- Maker
- ROHM
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Voltage detector IC: 2.6V±1%, -Reset ODO
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
BU45L304GVoltage supervisor, ROHMVoltage supervisorROHM
- What it is
- Voltage supervisor
- Maker
- ROHM
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Voltage detector IC: 3.0V±1%, -Reset ODO, Rdt=400ms
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
IXD5120N412NR-GVoltage supervisor, IXYSVoltage supervisorIXYS
- What it is
- Voltage supervisor
- Maker
- IXYS
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Voltage detector IC: 4.1V±2% -Reset ODO
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
IXD5127N18KNRVoltage supervisor, IXYSVoltage supervisorIXYS
- What it is
- Voltage supervisor
- Maker
- IXYS
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Voltage detector IC: 1.8V±0.8%, +Reset ODO, -MR, 800ms Rt delay
- 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.
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.
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.
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.
RF amplifier
Voltage, board powered, on the output pin that the bias resistor or choke feeds.
Working, it reads
The output pin sits at the device voltage the datasheet gives, a few volts, below the supply.
Dead, it reads
- Output pin at 0 V, or near 0 Ω to ground with the power off: shorted inside.
- Output pin at the full supply voltage: open inside, no current flowing.
- On the board:
- Measured on the board with power on; the bias network is part of the reading.
- 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 figures depend on the part and its bias resistor. 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.
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.
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 MB
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 MB
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 152 more parts.
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