SMD code U27
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.
U27 on a chip capacitor
270 nF
270 nF capacitor
The u is both the decimal point and the unit: 270 nF.
Check it with a meter
Lift one end and measure it on a capacitance range. A good one reads close to 270 nF. In circuit the meter also sees everything connected across it, so the reading means little until it is out. A failed one usually reads near 0 Ω, or a steady low resistance, on the ohms range, often from a crack. On the board a shorted capacitor shorts its whole rail. A failed reading does not change what to fit: the marking still says 270 nF.
On a transistor or diode body (SOT-23, SOT-23-5, SOT-89-5), U27 is a part code instead. Those parts are listed below.
10 parts are printed U27
Not sure which one you have?
Answer up to 4 quick questions and these 10 parts are ranked, with a meter test that settles it. It works on a dead part too.
AP1150ADS27SOT-23-5LDO regulator, 5 pins, AKM SemiconductorLDO regulatorSOT-23-55 pinsAKM Semiconductor
- What it is
- LDO regulator
- Maker
- AKM Semiconductor
- Package
- SOT-23-5
- Pins
- 5
- Details
- Linear voltage regulator IC: LDO, 2.7V±1.5%, 200mA, +CE
- Source
- Published code list
Is it dead? The meter test is below: Voltage regulator.
SMTPA200SMB2 pins, SGS-Thomson MicroelectronicsNot recordedSMB2 pinsSGS-Thomson Microelectronics
- What it is
- Not recorded
- Maker
- SGS-Thomson Microelectronics
- Package
- SMB
- Pins
- 2
- Details
- TVS: 200V, 50A(1ms), 5W, Bidirectional
- Source
- Published code list
Is it dead? The meter test is below: TVS or ESD protection diode.
SMTPB200SMC2 pins, SGS-Thomson MicroelectronicsNot recordedSMC2 pinsSGS-Thomson Microelectronics
- What it is
- Not recorded
- Maker
- SGS-Thomson Microelectronics
- Package
- SMC
- Pins
- 2
- Details
- TVS: 200V, 100A, 5W(1ms), Bidirectional
- Source
- Published code list
Is it dead? The meter test is below: TVS or ESD protection diode.
XC6383E271MSOT-23-5DC-DC converter, 5 pins, TorexDC-DC converterSOT-23-55 pinsTorex
- What it is
- DC-DC converter
- Maker
- Torex
- Package
- SOT-23-5
- Pins
- 5
- Details
- DC/DC voltage converter IC: PFM st-up, 2.7V±2.5%, 400mA, 100kHz, internal Vdd
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
XC6383E271PSOT-89-5DC-DC converter, 5 pins, TorexDC-DC converterSOT-89-55 pinsTorex
- What it is
- DC-DC converter
- Maker
- Torex
- Package
- SOT-89-5
- Pins
- 5
- Details
- DC/DC voltage converter IC: PFM st-up, 2.7V±2.5%, 400mA, 100kHz, int. Vdd
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
XC9226A276MSOT-23-5DC-DC converter, 5 pins, TorexDC-DC converterSOT-23-55 pinsTorex
- What it is
- DC-DC converter
- Maker
- Torex
- Package
- SOT-23-5
- Pins
- 5
- Details
- DC/DC voltage converter IC: PWM/PFM st-dwn, 600kHz, 2.7V±1%, 600mA, +CE
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
XC9226B276MSOT-23-5DC-DC converter, 5 pins, TorexDC-DC converterSOT-23-55 pinsTorex
- What it is
- DC-DC converter
- Maker
- Torex
- Package
- SOT-23-5
- Pins
- 5
- Details
- DC/DC voltage converter IC: PWM/PFM st-dwn, 600kHz, 2.7V±1%, 600mA, -CE
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
XC9226C276MSOT-23-5DC-DC converter, 5 pins, TorexDC-DC converterSOT-23-55 pinsTorex
- What it is
- DC-DC converter
- Maker
- Torex
- Package
- SOT-23-5
- Pins
- 5
- Details
- DC/DC voltage converter IC: PWM/PFM st-dwn, 600kHz, 2.7V±1%, 600mA, +CE, PDR
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
XC9226D276MSOT-23-5DC-DC converter, 5 pins, TorexDC-DC converterSOT-23-55 pinsTorex
- What it is
- DC-DC converter
- Maker
- Torex
- Package
- SOT-23-5
- Pins
- 5
- Details
- DC/DC voltage converter IC: PWM/PFM st-dwn, 600kHz, 2.7V±1%, 600mA, -CE, PUR
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
1 more part has no package on record
QS5U27P-channel MOSFET, ROHMP-channel MOSFETNot recordedNot recordedROHM
- What it is
- P-channel MOSFET
- Maker
- ROHM
- Package
- Not recorded
- Pins
- Not recorded
- Details
- P-Channel MOSFET + Schottky Barrier Diode
- Source
- Published code list
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.
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.
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.
TVS or ESD protection diode
Diode range, from the protected line to ground, part lifted if you can.
Working, it reads
A one-way part reads about 0.6 to 0.8 V forward and open in reverse. A two-way part reads open both ways. Arrays with several lines read as the datasheet's diagram draws them.
Dead, it reads
- From the line to ground, the same reading both ways, near 0 V with a continuous beep: shorted.
- A reading both ways on a one-way part: leaky.
- A one-way part open both ways: failed open.
- On the board
- , a line reading shorted to ground can be this part or anything else on that line. Lift it: if the short goes with it, it has failed.
- Compare:
- The same part on the next line or connector pin is the healthy reading to compare with.
- Watch for:
- A two-way part reads open both ways when it is good, exactly like one that has failed open. The meter cannot tell them apart; an identical part on the next line can.
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.
Printed with a code easy to misread as U27
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 U27
For a marking with its end worn or burnt off. Each code has a page of its own.
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