SMD code U1 in SOT-143
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.
4 parts in SOT-143 are printed U1
Not sure which one you have?
Answer up to 4 quick questions and these 22 parts are ranked, with a meter test that settles it. It works on a dead part too.
BGX50ASOT-143RF amplifier (MMIC), 4 pins, InfineonRF amplifier (MMIC)4 pinsInfineon
- What it is
- RF amplifier (MMIC)
- Maker
- Infineon
- Package
- SOT-143
- Pins
- 4
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: RF amplifier.
3SK283SOT-1434 pins, ToshibaNot recorded4 pinsToshiba
- What it is
- Not recorded
- Maker
- Toshiba
- Package
- SOT-143
- Pins
- 4
- Details
- n-FET-d: GaAs, 2-Gate, UHF-TV-Tuner, 6V, Idss=4..16mA, Up=0,5..1,5V
- Source
- Published code list
Is it dead? The meter test is below: MOSFET.
R3111Q111CSOT-1434 pins, Nisshinbo Micro DevicesNot recorded4 pinsNisshinbo Micro Devices
- What it is
- Not recorded
- Maker
- Nisshinbo Micro Devices
- Package
- SOT-143
- Pins
- 4
- Details
- CMOS-IC: Voltage Detector 1,1V±2.0%, Reset Open drain output
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
TCM811LERCSOT-1434 pins, MicrochipNot recorded4 pinsMicrochip
- What it is
- Not recorded
- Maker
- Microchip
- Package
- SOT-143
- Pins
- 4
- Source
- Published code list
Is it dead? The meter test is below: This part.
11 more parts have no package on record. Nothing rules them out, so they stay.
AP8822C-21GIVoltage supervisor, Anwell SemiconductorVoltage supervisorNot recordedAnwell Semiconductor
- What it is
- Voltage supervisor
- Maker
- Anwell Semiconductor
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Voltage detector IC: 2.1V±2%, -Reset PPO, 200ms Rt delay, H-free
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
AP8822C-21GSVoltage supervisor, Anwell SemiconductorVoltage supervisorNot recordedAnwell Semiconductor
- What it is
- Voltage supervisor
- Maker
- Anwell Semiconductor
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Voltage detector IC: 2.1V±2%, -Reset PPO, 200ms Rt delay, H-free
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
AP8822C-21PIVoltage supervisor, Anwell SemiconductorVoltage supervisorNot recordedAnwell Semiconductor
- What it is
- Voltage supervisor
- Maker
- Anwell Semiconductor
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Voltage detector IC: 2.1V±2%, -Reset PPO, 200ms Rt delay
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
AP8822C-21PSVoltage supervisor, Anwell SemiconductorVoltage supervisorNot recordedAnwell Semiconductor
- What it is
- Voltage supervisor
- Maker
- Anwell Semiconductor
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Voltage detector IC: 2.1V±2%, -Reset PPO, 200ms Rt delay
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
BD45391GVoltage supervisor, ROHMVoltage supervisorNot recordedROHM
- What it is
- Voltage supervisor
- Maker
- ROHM
- Package
- Not recorded
- Pins
- Not recorded
- Details
- CMOS-IC: Voltage Detector 3,9V, -Reset Open drain output, 100ms
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
BL8067CB3ATR10LDO regulator, Shanghai BellingLDO regulatorNot recordedShanghai Belling
- What it is
- LDO regulator
- Maker
- Shanghai Belling
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Linear voltage regulator IC: LDO, 1.0V±2%, 300mA
- Source
- Published code list
Is it dead? The meter test is below: Voltage regulator.
BL8067CB3ATR11LDO regulator, Shanghai BellingLDO regulatorNot recordedShanghai Belling
- What it is
- LDO regulator
- Maker
- Shanghai Belling
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Linear voltage regulator IC: LDO, 1.1V±2%, 300mA
- Source
- Published code list
Is it dead? The meter test is below: Voltage regulator.
BL8067CB3ATR21LDO regulator, Shanghai BellingLDO regulatorNot recordedShanghai Belling
- What it is
- LDO regulator
- Maker
- Shanghai Belling
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Linear voltage regulator IC: LDO, 2.1V±2%, 300mA
- Source
- Published code list
Is it dead? The meter test is below: Voltage regulator.
BL8067CB3ATR31LDO regulator, Shanghai BellingLDO regulatorNot recordedShanghai Belling
- What it is
- LDO regulator
- Maker
- Shanghai Belling
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Linear voltage regulator IC: LDO, 3.1V±2%, 300mA
- Source
- Published code list
Is it dead? The meter test is below: Voltage regulator.
BL8067CB3ATR41LDO regulator, Shanghai BellingLDO regulatorNot recordedShanghai Belling
- What it is
- LDO regulator
- Maker
- Shanghai Belling
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Linear voltage regulator IC: LDO, 4.1V±2%, 300mA
- Source
- Published code list
Is it dead? The meter test is below: Voltage regulator.
EC95810C21C7IVoltage supervisor, E-CMOSVoltage supervisorNot recordedE-CMOS
- What it is
- Voltage supervisor
- Maker
- E-CMOS
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Voltage detector IC: 2.1V±2%, -Reset PPO, Td=200ms
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
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.
RF amplifier
Voltage, board powered, on the output pin that the bias resistor or choke feeds.
Working, it reads
The output pin sits at the device voltage the datasheet gives, a few volts, below the supply.
Dead, it reads
- Output pin at 0 V, or near 0 Ω to ground with the power off: shorted inside.
- Output pin at the full supply voltage: open inside, no current flowing.
- On the board:
- Measured on the board with power on; the bias network is part of the reading.
- 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 figures depend on the part and its bias resistor. 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.
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.
Integrated circuit
Voltage with the board powered; ohms from each pin to ground with it off.
Working, it reads
Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.
Dead, it reads
- A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
- Supply present, output stuck: failed, or its load has.
- On the board:
- A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
- Compare:
- The surest reference is the same IC on a working board, measured pin by pin.
- Watch for:
- Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
This part
Diode range and ohms range, part lifted.
Working, it reads
Depends on what it is. The datasheet, or an identical part, says.
Dead, it reads
- Between two pins, the same reading both ways, near 0 V with a continuous beep: shorted.
- Open between every pair of pins: failed open, or a part that reads open when working.
- 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.
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.
Printed with a code easy to misread as U1
One character differs, and it is one that is easy to confuse under a lamp. Each code has a page of its own.
Codes that begin with U1
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 47 more parts.
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