SMD code 3400
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.
3400 on a chip resistor
340 Ω
340 Ω resistor, 1%
340 followed by 0 zeros. Four digits is normally the 1% series.
Check it with a meter
Lift one end and measure across it. A good one reads 340 Ω within 1%. Measuring it in circuit reads the parallel combination of everything around it, which is almost always lower, never higher: well above 340 Ω on the board is a fault. Open, or well above 340 Ω, means it has failed: burnt, cracked or corroded. That does not change what to fit: the marking still says 340 Ω. 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, SOT-23-5, DFN), 3400 is a part code instead. Those parts are listed below.
18 parts are printed 3400
Not sure which one you have?
Answer up to 4 quick questions and these 18 parts are ranked, with a meter test that settles it. It works on a dead part too.
BL3400SOT-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
- 5.7A, 30V, 1.4W, N Channel, Power MOSFETs
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: N-channel MOSFET.
BL3400-3LSOT-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
- 5.7A, 30V, 1.4W, N Channel, Power MOSFETs
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: N-channel MOSFET.
BL3400-6LSOT-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
- 6.6A, 30V, 2W, N Channel, Power MOSFETs
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: N-channel MOSFET.
BL3400DF1DFNN-channel MOSFET, Galaxy MicroelectronicsN-channel MOSFETDFNNot recordedGalaxy Microelectronics
- What it is
- N-channel MOSFET
- Maker
- Galaxy Microelectronics
- Package
- DFN
- Pins
- Not recorded
- Details
- 6.6A, 30V, 2.4W, N Channel, Power MOSFETs
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: N-channel MOSFET.
BL3400ESOT-89N-channel MOSFET, 3 pins, Galaxy MicroelectronicsN-channel MOSFETSOT-893 pinsGalaxy Microelectronics
- What it is
- N-channel MOSFET
- Maker
- Galaxy Microelectronics
- Package
- SOT-89
- Pins
- 3
- Details
- 7A, 30V, 2W, N Channel, Power MOSFETs
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: N-channel MOSFET.
EM03N58MSOT-23N-channel MOSFET, 3 pins, ETEKN-channel MOSFETSOT-233 pinsETEK
- What it is
- N-channel MOSFET
- Maker
- ETEK
- Package
- SOT-23
- Pins
- 3
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: N-channel MOSFET.
FMOS3400ASOT-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.
FMOS3400A-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.
JMTJ3400ASOT-23Load switch, 3 pins, JieJieLoad switchSOT-233 pinsJieJie
- What it is
- Load switch
- Maker
- JieJie
- Package
- SOT-23
- Pins
- 3
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Load switch.
JMTL3400ASOT-23Load switch, 3 pins, JieJieLoad switchSOT-233 pinsJieJie
- What it is
- Load switch
- Maker
- JieJie
- Package
- SOT-23
- Pins
- 3
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Load switch.
SMG3400SOT-23MOSFET, 3 pins, SeCoSMOSFETSOT-233 pinsSeCoS
- What it is
- MOSFET
- Maker
- SeCoS
- Package
- SOT-23
- Pins
- 3
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: MOSFET.
SMS3400Y-CSOT-23MOSFET, 3 pins, SeCoSMOSFETSOT-233 pinsSeCoS
- What it is
- MOSFET
- Maker
- SeCoS
- Package
- SOT-23
- Pins
- 3
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: MOSFET.
SSM3400-CSOT-223MOSFET, 4 pins, SeCoSMOSFETSOT-2234 pinsSeCoS
- What it is
- MOSFET
- Maker
- SeCoS
- Package
- SOT-223
- Pins
- 4
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: MOSFET.
TBL3400SOT-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
- 5.7A, 30V, 1.4W, N Channel, Power MOSFETs
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: N-channel MOSFET.
1 more part has no package on record
JMTL2N7002KT5N-channel MOSFET, JieJieN-channel MOSFETNot recordedNot recordedJieJie
- What it is
- N-channel MOSFET
- Maker
- JieJie
- Package
- Not recorded
- Pins
- Not recorded
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: N-channel MOSFET.
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.
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.
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.
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.
Codes that begin with 3400
For a marking with its end worn or burnt off. Each code has a page of its own.
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