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WhatSMDSign in

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.

23 parts are printed B

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.

  • IRLMS1503SOT-23N-channel MOSFET, 3 pins, Infineon
    What it is
    N-channel MOSFET
    Maker
    Infineon
    Package
    SOT-23
    Pins
    3
    Details
    30V Single N-Channel Power MOSFET in a TSOP-6 (Micro 6) package
    Source
    From the manufacturer's datasheet

    Is it dead? The meter test is below: N-channel MOSFET.

    Datasheetfor IRLMS1503, opens in a new tab
  • RB520S-30SOD-523Schottky diode, 2 pins, JSCJ
    What it is
    Schottky diode
    Maker
    JSCJ
    Package
    SOD-523
    Pins
    2
    Details
    Schottky diode, 30 V, 0.2 A
    Source
    From the manufacturer's datasheet

    Is it dead? The meter test is below: Schottky diode.

    Datasheetfor RB520S-30, opens in a new tab
  • TLV809EA24DPWX2SONVoltage supervisor, 5 pins, Texas Instruments
    What it is
    Voltage supervisor
    Maker
    Texas Instruments
    Package
    X2SON
    Pins
    5
    Details
    Low Power 250-nA IQ and Small Size Supply Voltage Supervisors
    Source
    From the manufacturer's datasheet

    Is it dead? The meter test is below: Integrated circuit.

    Datasheetfor TLV809EA24DPW, opens in a new tab
  • VBUS05M1-02VSOD-523ESD protection diode, 2 pins, Vishay
    What it is
    ESD protection diode
    Maker
    Vishay
    Package
    SOD-523
    Pins
    2
    Details
    Low Capacitance Single Line ESD-Protection Diode in SOD-523
    Source
    From the manufacturer's datasheet

    Is it dead? The meter test is below: TVS or ESD protection diode.

    Datasheetfor VBUS05M1-02V, opens in a new tab
  • 19 more parts have no package on record
    • AON1606MOSFET, Alpha & Omega Semiconductor
      What it is
      MOSFET
      Maker
      Alpha & Omega Semiconductor
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Low-voltage (12-30 V) MOSFET
      Source
      From the manufacturer's datasheet

      Is it dead? The meter test is below: MOSFET.

      Datasheetfor AON1606, opens in a new tab
    • AON1606LMOSFET, Alpha & Omega Semiconductor
      What it is
      MOSFET
      Maker
      Alpha & Omega Semiconductor
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Low-voltage (12-30 V) MOSFET
      Source
      From the manufacturer's datasheet

      Is it dead? The meter test is below: MOSFET.

      Datasheetfor AON1606L, opens in a new tab
    • AOZ8S204BLS-03ESD protection diode, Alpha & 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
      From the manufacturer's datasheet

      Is it dead? The meter test is below: TVS or ESD protection diode.

      Datasheetfor AOZ8S204BLS-03, opens in a new tab
    • AOZ8S204BLS-05ESD protection diode, Alpha & 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
      From the manufacturer's datasheet

      Is it dead? The meter test is below: TVS or ESD protection diode.

      Datasheetfor AOZ8S204BLS-05, opens in a new tab
    • AOZ8S322UD2-03ESD protection diode, Alpha & 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
      From the manufacturer's datasheet

      Is it dead? The meter test is below: TVS or ESD protection diode.

      Datasheetfor AOZ8S322UD2-03, opens in a new tab
    • AOZ8829ADI-05ESD protection diode, Alpha & 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
      From the manufacturer's datasheet

      Is it dead? The meter test is below: TVS or ESD protection diode.

      Datasheetfor AOZ8829ADI-05, opens in a new tab
    • BAS16-03WSwitching diode, Infineon
      What it is
      Switching diode
      Maker
      Infineon
      Package
      Not recorded
      Pins
      Not recorded
      Source
      From the manufacturer's datasheet

      Is it dead? The meter test is below: Silicon diode.

      Datasheetfor BAS16-03W, opens in a new tab
    • BAT15-098LRHSchottky diode, Infineon
      What it is
      Schottky diode
      Maker
      Infineon
      Package
      Not recorded
      Pins
      Not recorded
      Source
      From the manufacturer's datasheet

      Is it dead? The meter test is below: Schottky diode.

      Datasheetfor BAT15-098LRH, opens in a new tab
    • BB555-02VInfineon
      What it is
      Not recorded
      Maker
      Infineon
      Package
      Not recorded
      Pins
      Not recorded
      Source
      From the manufacturer's datasheet

      Is it dead? The meter test is below: This part.

      Datasheetfor BB555-02V, opens in a new tab
    • ESD5V0AE1ESD protection diode, JSCJ
      What it is
      ESD protection diode
      Maker
      JSCJ
      Package
      Not recorded
      Pins
      Not recorded
      Details
      ESD protection diode, VRWM 5 V
      Source
      From the manufacturer's datasheet

      Is it dead? The meter test is below: TVS or ESD protection diode.

      Datasheetfor ESD5V0AE1, opens in a new tab
    • ESD217-B1-02ELESD protection diode, Infineon
      What it is
      ESD protection diode
      Maker
      Infineon
      Package
      Not recorded
      Pins
      Not recorded
      Source
      From the manufacturer's datasheet

      Is it dead? The meter test is below: TVS or ESD protection diode.

      Datasheetfor ESD217-B1-02EL, opens in a new tab
    • ESDM5V0AE1ESD protection diode, JSCJ
      What it is
      ESD protection diode
      Maker
      JSCJ
      Package
      Not recorded
      Pins
      Not recorded
      Details
      ESD protection diode, VRWM 5 V
      Source
      From the manufacturer's datasheet

      Is it dead? The meter test is below: TVS or ESD protection diode.

      Datasheetfor ESDM5V0AE1, opens in a new tab
    • IRLML2803N-channel MOSFET, Infineon
      What it is
      N-channel MOSFET
      Maker
      Infineon
      Package
      Not recorded
      Pins
      Not recorded
      Details
      30V Single N-Channel Power MOSFET in a Micro 3 package
      Source
      From the manufacturer's datasheet

      Is it dead? The meter test is below: N-channel MOSFET.

      Datasheetfor IRLML2803, opens in a new tab
    • PJSD05TMESD protection diode, Panjit
      What it is
      ESD protection diode
      Maker
      Panjit
      Package
      Not recorded
      Pins
      Not recorded
      Source
      From the manufacturer's datasheet

      Is it dead? The meter test is below: TVS or ESD protection diode.

      Datasheetfor PJSD05TM, opens in a new tab
    • PS140M-D32ESD protection diode, Panjit
      What it is
      ESD protection diode
      Maker
      Panjit
      Package
      Not recorded
      Pins
      Not recorded
      Source
      From the manufacturer's datasheet

      Is it dead? The meter test is below: TVS or ESD protection diode.

      Datasheetfor PS140M-D32, opens in a new tab
    • SS14MSchottky diode, Taiwan Semiconductor
      What it is
      Schottky diode
      Maker
      Taiwan Semiconductor
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Rectifier schottky
      Source
      From the manufacturer's datasheet

      Is it dead? The meter test is below: Schottky diode.

      Datasheetfor SS14M, opens in a new tab
    • SS14MHSchottky diode, Taiwan Semiconductor
      What it is
      Schottky diode
      Maker
      Taiwan Semiconductor
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Rectifier schottky
      Source
      From the manufacturer's datasheet

      Is it dead? The meter test is below: Schottky diode.

      Datasheetfor SS14MH, opens in a new tab
    • VCAN33A2-HT5ESD protection diode, Vishay
      What it is
      ESD protection diode
      Maker
      Vishay
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Bidirectional Symmetrical (BiSy) Low Capacitance, Dual-Line ESD Protection Diode in DFN1110-3A
      Source
      From the manufacturer's datasheet

      Is it dead? The meter test is below: TVS or ESD protection diode.

      Datasheetfor VCAN33A2-HT5, opens in a new tab
    • VCUT0714A-HD1ESD protection diode, Vishay
      What it is
      ESD protection diode
      Maker
      Vishay
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Bidirectional Asymmetrical (BiAs) Single Line ESD Protection Diode in LLP1006-2L
      Source
      From the manufacturer's datasheet

      Is it dead? The meter test is below: TVS or ESD protection diode.

      Datasheetfor VCUT0714A-HD1, opens in a new tab

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.

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.

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.

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.

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.

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 that begin with B

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 839 more parts.

Open this in the search to correct a character or try another package.