SMD code UAs
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.
The last letter, s, is lower case, which on NXP and Philips parts is a date or factory code, so it was set aside and UA was searched.
81 parts are printed UAs
Not sure which one you have?
Answer up to 4 quick questions and these 50 parts are ranked, with a meter test that settles it. It works on a dead part too.
BCR149TSOT-416Digital transistor (NPN, resistors built in), 3 pins, InfineonDigital transistor (NPN, resistors built in)SOT-4163 pinsInfineon
- What it is
- Digital transistor (NPN, resistors built in)
- Maker
- Infineon
- Package
- SOT-416
- Pins
- 3
- Details
- Si-npn-Digi: Sw, 50V, 70mA, 250mW, R1=47k, 150MHz
- Source
- Published code list
Is it dead? The meter test is below: Digital transistor.
BD53E57GSOT-23-5Voltage supervisor, 5 pins, ROHMVoltage supervisorSOT-23-55 pinsROHM
- What it is
- Voltage supervisor
- Maker
- ROHM
- Package
- SOT-23-5
- Pins
- 5
- Details
- Free Delay Time Setting CMOS Voltage Detector IC
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
BZB84-C2V7SOT-23Zener diode, 3 pinsZener diodeSOT-233 pinsNot recorded
- What it is
- Zener diode
- Maker
- Not recorded
- Package
- SOT-23
- Pins
- 3
- Details
- 2.7V Dual Zener Diodes
- Source
- Published code list
Is it dead? The meter test is below: Zener diode.
CHT4401WPTSOT-323NPN transistor, 3 pins, Chenmko EnterpriseNPN transistorSOT-3233 pinsChenmko Enterprise
- What it is
- NPN transistor
- Maker
- Chenmko Enterprise
- Package
- SOT-323
- Pins
- 3
- Details
- NPN transistor: AF, Sw, 40V, 600mA, B=100..300, 250MHz
- Source
- Published code list
Is it dead? The meter test is below: NPN transistor.
FUES1ASMA2 pins, FagNot recordedSMA2 pinsFag
- What it is
- Not recorded
- Maker
- Fag
- Package
- SMA
- Pins
- 2
- Details
- Si-diode: UltraFast Recovery Rect, 50V, 1A, <25ns
- Source
- Published code list
Is it dead? The meter test is below: Silicon diode.
GDZ12B-V-GSOD-323Zener diode, 2 pins, VishayZener diodeSOD-3232 pinsVishay
- What it is
- Zener diode
- Maker
- Vishay
- Package
- SOD-323
- Pins
- 2
- Details
- Zener diode: 11.74..12.24V, Izt=5mA, Zzt=30, 200mW
- Source
- Published code list
Is it dead? The meter test is below: Zener diode.
KDV154SOD-1232 pins, KECNot recordedSOD-1232 pinsKEC
- What it is
- Not recorded
- Maker
- KEC
- Package
- SOD-123
- Pins
- 2
- Details
- C-diode: VCO for UHF-Band Radio
- Source
- Published code list
Is it dead? The meter test is below: Silicon diode.
8 more parts have no package on record
BD53E57G-MVoltage supervisor, ROHMVoltage supervisorNot recordedNot recordedROHM
- What it is
- Voltage supervisor
- Maker
- ROHM
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Voltage detector IC: 5.7V±1%, -Reset PPO
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
BD45301GVoltage supervisor, ROHMVoltage supervisorNot recordedNot recordedROHM
- What it is
- Voltage supervisor
- Maker
- ROHM
- Package
- Not recorded
- Pins
- Not recorded
- Details
- CMOS-IC: Voltage Detector 3V, -Reset Open drain output, 100ms
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
CZRER5V1B-HZener diode, ComchipZener diodeNot recordedNot recordedComchip
- What it is
- Zener diode
- Maker
- Comchip
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Zener diode: 4.97..5.232V, Zzt=50, Izt=5mA, 150mW
- Source
- Published code list
Is it dead? The meter test is below: Zener diode.
CZRF5V1BZener diode, ComchipZener diodeNot recordedNot recordedComchip
- What it is
- Zener diode
- Maker
- Comchip
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Zener diode: 4.97..5.23V, Izt=5mA, Zzt=50, 200mW
- Source
- Published code list
Is it dead? The meter test is below: Zener diode.
CZRQR5V1BZener diode, ComchipZener diodeNot recordedNot recordedComchip
- What it is
- Zener diode
- Maker
- Comchip
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Zener diode: 4.97..5.23V, Izt=5mA, Zzt=50, 125mW
- Source
- Published code list
Is it dead? The meter test is below: Zener diode.
CZRU5V1BZener diode, ComchipZener diodeNot recordedNot recordedComchip
- What it is
- Zener diode
- Maker
- Comchip
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Zener diode: 4.97..5.23V, Izt=5mA, Zzt=50, 150mW
- Source
- Published code list
Is it dead? The meter test is below: Zener diode.
IXD5127C16JNRVoltage supervisor, IXYSVoltage supervisorNot recordedNot recordedIXYS
- What it is
- Voltage supervisor
- Maker
- IXYS
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Voltage detector IC: 1.6V±0.8%,+Reset PPO, -MR, 400ms Rt delay
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
KDV154EKECNot recordedNot recordedNot recordedKEC
- What it is
- Not recorded
- Maker
- KEC
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Capacitance diode: VCO for UHF-Band, 20V, 13.9..4.5pF(6..2V)
- Source
- Published code list
Is it dead? The meter test is below: Silicon diode.
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.
Digital transistor
Ohms range, part lifted. The datasheet gives the built-in resistors: R1 in series with the base, R2 from base to emitter.
Working, it reads
Base to emitter reads about R1 plus R2 either way round, about 20 kΩ on a 10 k and 10 k part, give or take their wide tolerance. Collector to emitter reads open. A part with no R2 reads a junction behind R1 one way instead.
Dead, it reads
- Collector to emitter the same both ways, near 0 Ω with a continuous beep: shorted.
- From the base, open or far above R1 plus R2: R1 has failed. Static damage shows here most often.
- Base to emitter near 0 Ω: failed short.
- 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:
- The readings depend on the resistor values, so an identical part elsewhere on the board is the surest reference. Measure it the same way.
- Watch for:
- On the diode range a good part with 10 kΩ resistors reads open on every pair, so a good part looks dead there. Use the ohms range.
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.
Zener diode
Diode range for the forward check, part lifted, red probe on the anode. A bench supply for the Zener voltage.
Working, it reads
About 0.6 to 0.8 V forward and open in reverse on the diode range. Its Zener voltage shows only on a supply: feed it through a resistor that sets about 5 mA, cathode to positive, read quickly, and it should hold near its rated voltage.
Dead, it reads
- The same reading both ways round, near 0 V with a continuous beep or the same middling value: shorted.
- Open both ways, forward too: failed open.
- Holds well off its rated voltage on the supply test: drifted.
- A soft knee, or a voltage that creeps on the supply test: leaky.
- 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.
- Watch for:
- A meter's diode range stops at about 2 to 3 V, so almost every Zener reads open in reverse on it, good or bad; a 3 V meter may just show a 2.4 or 2.7 V part. Above about 3 V the meter cannot tell a Zener from a plain diode.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
NPN transistor
Diode range, part lifted or its base leg off the pad.
Working, it reads
Red probe on the base reads about 0.6 to 0.75 V to the emitter and to the collector, and open the other way round. Collector to emitter reads open both ways.
Dead, it reads
- Collector to emitter the same both ways, near 0 V with a continuous beep: shorted. The commonest failure.
- The base the same both ways to another pin, near 0 V or a middling value: a shorted junction.
- Only one junction reads, or none: a junction has failed open. It then looks like a diode.
- A reading the wrong way round, where it should be open: leaky.
- 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.
- Watch for:
- A pair of diodes with a common pin reads just like a transistor, and some transistors carry a built-in diode or resistor. The datasheet says which.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
Silicon diode
Diode range, part lifted or one leg off the pad. Red probe on the anode.
Working, it reads
About 0.5 to 0.8 V anode to cathode, and open the other way. Small switching diodes read about 0.6 to 0.7 V; large rectifiers can read a little lower.
Dead, it reads
- The same reading both ways round, near 0 V with a continuous beep or the same middling value: shorted.
- Open both ways: failed open.
- A reading the wrong way round as well: leaky.
- 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.
- Watch for:
- A three-pin body can hold two diodes. With a common pin they read two junctions from that pin, just like a transistor; in series they read two drops end to end. Test each pair the datasheet names.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
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