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SMD code B3 in SOT-23-5

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.

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.

15 parts have no package on record. Nothing rules them out, so they stay.

  • KDS121Switching diode, KECSwitching diodeKEC
    What it is
    Switching diode
    Maker
    KEC
    Package
    Not recorded
    Pins
    Not recorded
    Source
    Manufacturer datasheet

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

  • KDS121ESwitching diode, KECSwitching diodeKEC
    What it is
    Switching diode
    Maker
    KEC
    Package
    Not recorded
    Pins
    Not recorded
    Source
    Manufacturer datasheet

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

  • KDS121VSwitching diode, KECSwitching diodeKEC
    What it is
    Switching diode
    Maker
    KEC
    Package
    Not recorded
    Pins
    Not recorded
    Source
    Manufacturer datasheet

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

  • LTVS16H12T5GESD protection diode, LRCESD protection diodeLRC
    What it is
    ESD protection diode
    Maker
    LRC
    Package
    Not recorded
    Pins
    Not recorded
    Details
    ESD protection diode, VRWM 12 V, IR @VRWM 0.5 μA, VBR Min 13.5 V
    Source
    Manufacturer datasheet

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

  • NC7SZ86FHLogic gate, onsemiLogic gateonsemi
    What it is
    Logic gate
    Maker
    onsemi
    Package
    Not recorded
    Pins
    Not recorded
    Details
    TinyLogic UHS Two-Input Exclusive-OR Gate
    Source
    Manufacturer datasheet

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

  • NC7SZ86L6Logic gate, onsemiLogic gateonsemi
    What it is
    Logic gate
    Maker
    onsemi
    Package
    Not recorded
    Pins
    Not recorded
    Details
    TinyLogic UHS Two-Input Exclusive-OR Gate
    Source
    Manufacturer datasheet

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

  • S-LTVS16H12T5GESD protection diode, LRCESD protection diodeLRC
    What it is
    ESD protection diode
    Maker
    LRC
    Package
    Not recorded
    Pins
    Not recorded
    Details
    ESD protection diode, VRWM 12 V, IR @VRWM 0.5 μA, VBR Min 13.5 V
    Source
    Manufacturer datasheet

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

  • TSCD053WSSchottky diode, Taitron ComponentsSchottky diodeTaitron Components
    What it is
    Schottky diode
    Maker
    Taitron Components
    Package
    Not recorded
    Pins
    Not recorded
    Details
    Low Profile Chip Type Schottky Rectifier
    Source
    Manufacturer datasheet

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

  • TSCD0530Schottky diode, Taitron ComponentsSchottky diodeTaitron Components
    What it is
    Schottky diode
    Maker
    Taitron Components
    Package
    Not recorded
    Pins
    Not recorded
    Details
    Low Profile Chip Type Schottky Rectifier
    Source
    Manufacturer datasheet

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

  • TSD053WSchottky diode, Taitron ComponentsSchottky diodeTaitron Components
    What it is
    Schottky diode
    Maker
    Taitron Components
    Package
    Not recorded
    Pins
    Not recorded
    Details
    Schottky Barrier Diodes (Two Terminals)
    Source
    Manufacturer datasheet

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

  • TWT4148C-121F5Switching diode, Taitron ComponentsSwitching diodeTaitron Components
    What it is
    Switching diode
    Maker
    Taitron Components
    Package
    Not recorded
    Pins
    Not recorded
    Details
    SMD Switching Diodes (Three Terminals)
    Source
    Manufacturer datasheet

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

  • 1SS361CTToshibaNot recordedToshiba
    What it is
    Not recorded
    Maker
    Toshiba
    Package
    Not recorded
    Pins
    Not recorded
    Details
    dual cc fast sw diode 80V 100mA
    Source
    Published code list

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

  • 1SS361FToshibaNot recordedToshiba
    What it is
    Not recorded
    Maker
    Toshiba
    Package
    Not recorded
    Pins
    Not recorded
    Details
    Si-diode: 2x Sw, U-Fast, 85V, 100mA, 150mW, Vf<1,2V(0.1A), <4ns
    Source
    Published code list

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

  • 2SC1621RenesasNot recordedRenesas
    What it is
    Not recorded
    Maker
    Renesas
    Package
    Not recorded
    Pins
    3
    Details
    NPN High Speed Switch 20v 200mA
    Source
    Published code list

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

  • 2SC4931-3Sanyo ElectricNot recordedSanyo Electric
    What it is
    Not recorded
    Maker
    Sanyo Electric
    Package
    Not recorded
    Pins
    Not recorded
    Details
    Si-npn: VHF/UHF, LN, 16V, 50mA, 100mW, B=135..270, 9GHz
    Source
    Published code list

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

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.

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.

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.

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.

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.

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