SMD code UW in SMB
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.
1 part in SMB is printed UW
Not sure which one you have?
Answer up to 4 quick questions and these 30 parts are ranked, with a meter test that settles it. It works on a dead part too.
SMBJ130CASMBTVS diode, 2 pins, Fagor ElectronicaTVS diode2 pinsFagor Electronica
- What it is
- TVS diode
- Maker
- Fagor Electronica
- Package
- SMB
- Pins
- 2
- Source
- Published code list
Is it dead? The meter test is below: TVS or ESD protection diode.
14 more parts have no package on record. Nothing rules them out, so they stay.
ACZRQC30VB-HFZener diode, ComchipZener diodeNot recordedComchip
- What it is
- Zener diode
- Maker
- Comchip
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 30 V 0.125 mW zener diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
ACZRUC30VB-HFZener diode, ComchipZener diodeNot recordedComchip
- What it is
- Zener diode
- Maker
- Comchip
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 30.75 V 0.15 mW zener diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
BGU7003WRF amplifier (MMIC), 6 pins, NXPRF amplifier (MMIC)6 pinsNXP
- What it is
- RF amplifier (MMIC)
- Maker
- NXP
- Package
- Not recorded
- Pins
- 6
- Details
- Wideband silicon germanium low-noise amplifier MMIC
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: RF amplifier.
CZRFR30VB-HFZener diode, ComchipZener diodeNot recordedComchip
- What it is
- Zener diode
- Maker
- Comchip
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 30 V 0.2 mW zener diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
CZRQC30VB-HFZener diode, ComchipZener diodeNot recordedComchip
- What it is
- Zener diode
- Maker
- Comchip
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 30 V 0.125 mW zener diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
CZRU30VB-HFZener diode, ComchipZener diodeNot recordedComchip
- What it is
- Zener diode
- Maker
- Comchip
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 30 V 0.15 mW zener diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
CZRUR30VB-HFZener diode, ComchipZener diodeNot recordedComchip
- What it is
- Zener diode
- Maker
- Comchip
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 30 V 0.15 mW zener diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
KDR331VSchottky diode, KECSchottky diodeNot recordedKEC
- What it is
- Schottky diode
- Maker
- KEC
- Package
- Not recorded
- Pins
- Not recorded
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
KDS4148WSwitching diode, KECSwitching diodeNot recordedKEC
- What it is
- Switching diode
- Maker
- KEC
- Package
- Not recorded
- Pins
- Not recorded
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
TST0051C-331F5Schottky diode, Taitron ComponentsSchottky diodeNot recordedTaitron Components
- What it is
- Schottky diode
- Maker
- Taitron Components
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Schottky Barrier Diodes (Multiple Terminals)
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
TST0051C-331WTSchottky diode, Taitron ComponentsSchottky diodeNot recordedTaitron Components
- What it is
- Schottky diode
- Maker
- Taitron Components
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Schottky Barrier Diodes (Multiple Terminals)
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
VS24VUA1VWMTVS diode, ROHMTVS diodeNot recordedROHM
- What it is
- TVS diode
- Maker
- ROHM
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Transient Voltage Suppressor
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
VS24VUA1VWMTFTVS diode, ROHMTVS diodeNot recordedROHM
- What it is
- TVS diode
- Maker
- ROHM
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Transient Voltage Suppressor
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
74LVC1G32FW4Diodes IncorporatedNot recordedNot recordedDiodes Incorporated
- What it is
- Not recorded
- Maker
- Diodes Incorporated
- Package
- Not recorded
- Pins
- Not recorded
- Details
- CMOS logic IC: 2-input OR gate
- 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.
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.
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.
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.
Schottky diode
Diode range, part lifted or one leg off the pad. Red probe on the anode.
Working, it reads
About 0.15 to 0.45 V anode to cathode, roughly half a silicon diode, and open the other way.
Dead, it reads
- The same reading both ways round, near 0 V with a continuous beep or the same middling value: shorted.
- A reading the wrong way round as well: leaky.
- Open both ways: failed open.
- 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 large Schottky can read about 0.1 V forward and beep like a short, and leaks a little the wrong way when good, more when warm. It is shorted only if it reads the same both ways. Measure it cold, beside an identical cold one.
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.
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.
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