SMD code 3403
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.
3403 on a chip resistor
340 kΩ
340 kΩ resistor, 1%
340 followed by 3 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 kΩ within 1%. Measuring it in circuit reads the parallel combination of everything around it, which is almost always lower, never higher: well above 340 kΩ on the board is a fault. Open, or well above 340 kΩ, means it has failed: burnt, cracked or corroded. That does not change what to fit: the marking still says 340 kΩ. 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 (DFN, SOT-23, SOT-323), 3403 is a part code instead. Those parts are listed below.
6 parts are printed 3403
Not sure which one you have?
Answer up to 4 quick questions and these 6 parts are ranked, with a meter test that settles it. It works on a dead part too.
BL3403SOT-23P-channel MOSFET, Galaxy MicroelectronicsP-channel MOSFETSOT-23Galaxy Microelectronics
- What it is
- P-channel MOSFET
- Maker
- Galaxy Microelectronics
- Package
- SOT-23
- Pins
- 3
- Details
- 2.6A, 30V, 1W, P Channel, Power MOSFETs
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: P-channel MOSFET.
BL3403WSOT-323P-channel MOSFET, Galaxy MicroelectronicsP-channel MOSFETSOT-323Galaxy Microelectronics
- What it is
- P-channel MOSFET
- Maker
- Galaxy Microelectronics
- Package
- SOT-323
- Pins
- 3
- Details
- 1.5A, 30V, 0.35W, P Channel, Power MOSFETs
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: P-channel MOSFET.
SMG3403-CSOT-23MOSFET, SeCoSMOSFETSOT-23SeCoS
- What it is
- MOSFET
- Maker
- SeCoS
- Package
- SOT-23
- Pins
- 3
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: MOSFET.
TBL3403SOT-23N-channel MOSFET, Galaxy MicroelectronicsN-channel MOSFETSOT-23Galaxy Microelectronics
- What it is
- N-channel MOSFET
- Maker
- Galaxy Microelectronics
- Package
- SOT-23
- Pins
- 3
- Details
- 2.6A, 30V, 1W, P Channel, Power MOSFETs
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: N-channel MOSFET.
MTP3403N3SOT-23P-channel MOSFET, CYStekP-channel MOSFETSOT-23CYStek
- What it is
- P-channel MOSFET
- Maker
- CYStek
- Package
- SOT-23
- Pins
- 3
- Details
- -30 V, -3.6 A P-channel MOSFET
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: P-channel MOSFET.
1 more part has no package on record
SM3403PSQGP-channel MOSFET, Sinopower SemiconductorP-channel MOSFETNot recordedSinopower Semiconductor
- What it is
- P-channel MOSFET
- Maker
- Sinopower Semiconductor
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 20 V, 25 A P-channel MOSFET
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: P-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.
P-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 drain, black on the source: 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. 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.
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 3403
For a marking with its end worn or burnt off. Each code has a page of its own.
Did you find your part?
Open this in the search to correct a character or try another package.