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SMD code GD3

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 are printed GD3

Not sure which one you have?

Answer up to 4 quick questions and these 3 parts are ranked, with a meter test that settles it. It works on a dead part too.

  • FP6861G-C1S5CTRSOT-23-5Load switch, 5 pins, FitipowerLoad switchSOT-23-55 pinsFitipower
    What it is
    Load switch
    Maker
    Fitipower
    Package
    SOT-23-5
    Pins
    5
    Details
    Single-Channel Power Distribution Switch Applications 顯示器 集線器
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: Load switch.

  • SMV1213-004LFSOT-23Varicap diode, 3 pins, SkyworksVaricap diodeSOT-233 pinsSkyworks
    What it is
    Varicap diode
    Maker
    Skyworks
    Package
    SOT-23
    Pins
    3
    Details
    SMV121x Series: Hyperabrupt Junction Tuning Varactors
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: PIN diode or varicap.

  • BCW33SOT-23NPN transistor, 3 pins, ROHMNPN transistorSOT-233 pinsROHM
    What it is
    NPN transistor
    Maker
    ROHM
    Package
    SOT-23
    Pins
    3
    Details
    Bipolar transistor, 45 V, 0.1 A
    Source
    Published code list

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

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.

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.

PIN diode or varicap

Diode range, part lifted or one leg off the pad. Red probe on the anode.

Working, it reads

About 0.6 to 0.9 V anode to cathode, 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.
  • 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 varicap that has drifted in capacitance reads normal on a meter. Only a capacitance meter or the tuning itself shows it.

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.

Printed with a code easy to misread as GD3

One character differs, and it is one that is easy to confuse under a lamp. Each code has a page of its own.

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