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SMD code 3W in SOT-343

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.

2 parts in SOT-343 are printed 3W

Not sure which one you have?

Answer up to 4 quick questions and these 4 parts are ranked, with a meter test that settles it. It works on a dead part too.

  • CH483KPTSOT-343Chenmko EnterpriseNot recordedChenmko Enterprise
    What it is
    Not recorded
    Maker
    Chenmko Enterprise
    Package
    SOT-343
    Pins
    4
    Details
    Diode: Dual, SBD, 30V, 200mA, Vf<0.5V(200mA)
    Source
    Published code list

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

  • RQ5RW39CASOT-343RicohNot recordedRicoh
    What it is
    Not recorded
    Maker
    Ricoh
    Package
    SOT-343
    Pins
    4
    Details
    VR-IC: LDO, 3,9V±2%, 150mA
    Source
    Published code list

    Is it dead? The meter test is below: Voltage regulator.

  • 2 more parts have no package on record. Nothing rules them out, so they stay.
    • CH483KGPSchottky diode, ChenmkoSchottky diodeChenmko
      What it is
      Schottky diode
      Maker
      Chenmko
      Package
      Not recorded
      Pins
      Not recorded
      Details
      SCHOTTKY BARRIER DIODE, 30 V, 0.2 A
      Source
      Manufacturer datasheet

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

      Datasheetfor CH483KGP, opens in a new tab
    • NSBC114EMXWDigital transistor (resistors built in), onsemiDigital transistor (resistors built in)onsemi
      What it is
      Digital transistor (resistors built in)
      Maker
      onsemi
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Bias Resistor Transistors (BRT) NSBCMXW Series
      Source
      Manufacturer datasheet

      Is it dead? The meter test is below: Digital transistor.

      Datasheetfor NSBC114EMXW, 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.

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.

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.

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.

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.

Codes that begin with 3W

For a marking with its end worn or burnt off. Each code has a page of its own.

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