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SMD code 3404

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.

3404 on a chip resistor

3.4 MΩ

3.4 MΩ resistor, 1%

340 followed by 4 zeros. Four digits is normally the 1% series.

Check it with a meter

Lift one end and measure across it. A good one reads 3.4 MΩ within 1%. Measuring it in circuit reads the parallel combination of everything around it, which is almost always lower, never higher: well above 3.4 MΩ on the board is a fault. Open, or well above 3.4 MΩ, means it has failed: burnt, cracked or corroded. That does not change what to fit: the marking still says 3.4 MΩ. A burnt resistor usually means the part it feeds drew too much, so find that before fitting a new one.

On a transistor or diode body (SOT-23, DFN, SOT-23-6), 3404 is a part code instead. Those parts are listed below.

27 parts are printed 3404

Not sure which one you have?

Answer up to 4 quick questions and these 27 parts are ranked, with a meter test that settles it. It works on a dead part too.

  • AO3404ASOT-23MOSFET, 3 pins, HXYMOSFETSOT-233 pinsHXY
    What it is
    MOSFET
    Maker
    HXY
    Package
    SOT-23
    Pins
    3
    Details
    Low-voltage (12-30 V) MOSFET
    Source
    Manufacturer datasheet

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

    Datasheetfor AO3404A, opens in a new tab
  • AO3456SOT-23MOSFET, 3 pins, HXYMOSFETSOT-233 pinsHXY
    What it is
    MOSFET
    Maker
    HXY
    Package
    SOT-23
    Pins
    3
    Details
    Low-voltage (12-30 V) MOSFET
    Source
    Manufacturer datasheet

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

    Datasheetfor AO3456, opens in a new tab
  • AS3404SOT-23N-channel MOSFET, 3 pins, HXYN-channel MOSFETSOT-233 pinsHXY
    What it is
    N-channel MOSFET
    Maker
    HXY
    Package
    SOT-23
    Pins
    3
    Details
    N-channel MOSFET, 30 V, 5.8 A
    Source
    Manufacturer datasheet

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

    Datasheetfor AS3404, opens in a new tab
  • BL3404SOT-23N-channel MOSFET, 3 pins, Galaxy MicroelectronicsN-channel MOSFETSOT-233 pinsGalaxy Microelectronics
    What it is
    N-channel MOSFET
    Maker
    Galaxy Microelectronics
    Package
    SOT-23
    Pins
    3
    Details
    5.8A, 30V, 0.35W, N Channel, Power MOSFETs
    Source
    Manufacturer datasheet

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

    Datasheetfor BL3404, opens in a new tab
  • BL3404-3LSOT-23N-channel MOSFET, 3 pins, Galaxy MicroelectronicsN-channel MOSFETSOT-233 pinsGalaxy Microelectronics
    What it is
    N-channel MOSFET
    Maker
    Galaxy Microelectronics
    Package
    SOT-23
    Pins
    3
    Details
    5.8A, 30V, 0.35W, N Channel, Power MOSFETs
    Source
    Manufacturer datasheet

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

    Datasheetfor BL3404-3L, opens in a new tab
  • BL3404-6LSOT-23-6N-channel MOSFET, 6 pins, Galaxy MicroelectronicsN-channel MOSFETSOT-23-66 pinsGalaxy Microelectronics
    What it is
    N-channel MOSFET
    Maker
    Galaxy Microelectronics
    Package
    SOT-23-6
    Pins
    6
    Details
    5.8A, 30V, 0.35W, N Channel, Power MOSFETs
    Source
    Manufacturer datasheet

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

    Datasheetfor BL3404-6L, opens in a new tab
  • BL3404DF1DFNN-channel MOSFET, Galaxy MicroelectronicsN-channel MOSFETDFNNot recordedGalaxy Microelectronics
    What it is
    N-channel MOSFET
    Maker
    Galaxy Microelectronics
    Package
    DFN
    Pins
    Not recorded
    Details
    5.8A, 30V, 2W, N Channel, Power MOSFETs
    Source
    Manufacturer datasheet

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

    Datasheetfor BL3404DF1, opens in a new tab
  • BL3404RSOT-223N-channel MOSFET, 4 pins, Galaxy MicroelectronicsN-channel MOSFETSOT-2234 pinsGalaxy Microelectronics
    What it is
    N-channel MOSFET
    Maker
    Galaxy Microelectronics
    Package
    SOT-223
    Pins
    4
    Details
    5.8A, 30V, 3W, N Channel, Power MOSFETs
    Source
    Manufacturer datasheet

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

    Datasheetfor BL3404R, opens in a new tab
  • BSS306NH6327SOT-23N-channel MOSFET, 3 pins, HXYN-channel MOSFETSOT-233 pinsHXY
    What it is
    N-channel MOSFET
    Maker
    HXY
    Package
    SOT-23
    Pins
    3
    Details
    N-channel MOSFET, 30 V, 5.8 A
    Source
    Manufacturer datasheet

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

    Datasheetfor BSS306NH6327, opens in a new tab
  • FMOS3404ASOT-23MOSFET, 3 pins, Formosa MicrosemiMOSFETSOT-233 pinsFormosa Microsemi
    What it is
    MOSFET
    Maker
    Formosa Microsemi
    Package
    SOT-23
    Pins
    3
    Source
    Manufacturer datasheet

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

    Datasheetfor FMOS3404A, opens in a new tab
  • FMOSK3404SOT-23MOSFET, 3 pins, Formosa MicrosemiMOSFETSOT-233 pinsFormosa Microsemi
    What it is
    MOSFET
    Maker
    Formosa Microsemi
    Package
    SOT-23
    Pins
    3
    Source
    Manufacturer datasheet

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

    Datasheetfor FMOSK3404, opens in a new tab
  • FMOSK3404-Q1SOT-23MOSFET, 3 pins, Formosa MicrosemiMOSFETSOT-233 pinsFormosa Microsemi
    What it is
    MOSFET
    Maker
    Formosa Microsemi
    Package
    SOT-23
    Pins
    3
    Source
    Manufacturer datasheet

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

    Datasheetfor FMOSK3404-Q1, opens in a new tab
  • GSF3404SOT-23N-channel MOSFET, 3 pins, Good-ArkN-channel MOSFETSOT-233 pinsGood-Ark
    What it is
    N-channel MOSFET
    Maker
    Good-Ark
    Package
    SOT-23
    Pins
    3
    Details
    N-channel MOSFET, 30 V
    Source
    Manufacturer datasheet

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

    Datasheetfor GSF3404, opens in a new tab
  • GSF3404BSOT-23N-channel MOSFET, 3 pins, Good-ArkN-channel MOSFETSOT-233 pinsGood-Ark
    What it is
    N-channel MOSFET
    Maker
    Good-Ark
    Package
    SOT-23
    Pins
    3
    Details
    N-channel MOSFET, 30 V
    Source
    Manufacturer datasheet

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

    Datasheetfor GSF3404B, opens in a new tab
  • HAO3456SOT-23N-channel MOSFET, 3 pins, HXYN-channel MOSFETSOT-233 pinsHXY
    What it is
    N-channel MOSFET
    Maker
    HXY
    Package
    SOT-23
    Pins
    3
    Details
    N-channel MOSFET, 30 V, 5.8 A
    Source
    Manufacturer datasheet

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

    Datasheetfor HAO3456, 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.

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.

Codes that begin with 3404

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 1 more part.

Did you find your part?

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