SMD code U4 in SOD-123F
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 SOD-123F are printed U4
Not sure which one you have?
Answer up to 4 quick questions and these 39 parts are ranked, with a meter test that settles it. It works on a dead part too.
SOD1U4SOD-123FRectifier, 2 pins, Galaxy MicroelectronicsRectifier2 pinsGalaxy Microelectronics
- What it is
- Rectifier
- Maker
- Galaxy Microelectronics
- Package
- SOD-123F
- Pins
- 2
- Details
- 1A, 200V, 25ns, Surface Mount Fast Recovery Rectifiers
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
SUF16FL-CSOD-123FRectifier, 2 pins, SeCoSRectifier2 pinsSeCoS
- What it is
- Rectifier
- Maker
- SeCoS
- Package
- SOD-123F
- Pins
- 2
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
TSOD1U4SOD-123FRectifier, 2 pins, Galaxy MicroelectronicsRectifier2 pinsGalaxy Microelectronics
- What it is
- Rectifier
- Maker
- Galaxy Microelectronics
- Package
- SOD-123F
- Pins
- 2
- Details
- 1A, 200V, 25ns, Surface Mount Fast Recovery Rectifiers
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
SL04-MSOD-123FSchottky diode, 2 pins, VishaySchottky diode2 pinsVishay
- What it is
- Schottky diode
- Maker
- Vishay
- Package
- SOD-123F
- Pins
- 2
- Details
- Diode: SBR, 40V, 1.1A, Vf<0.48V(1.1A)
- Source
- Published code list
Is it dead? The meter test is below: Schottky diode.
11 more parts have no package on record. Nothing rules them out, so they stay.
ACZRQC3V0B-HFZener diode, ComchipZener diodeNot recordedComchip
- What it is
- Zener diode
- Maker
- Comchip
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 3 V 0.125 mW zener diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
ACZRUC3V0B-HFZener diode, ComchipZener diodeNot recordedComchip
- What it is
- Zener diode
- Maker
- Comchip
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 3.08 V 0.15 mW zener diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
CZRFR3V0B-HFZener diode, ComchipZener diodeNot recordedComchip
- What it is
- Zener diode
- Maker
- Comchip
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 3 V 0.2 mW zener diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
CZRQC3V0B-HFZener diode, ComchipZener diodeNot recordedComchip
- What it is
- Zener diode
- Maker
- Comchip
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 3 V 0.125 mW zener diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
CZRU3V0B-HFZener diode, ComchipZener diodeNot recordedComchip
- What it is
- Zener diode
- Maker
- Comchip
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 3 V 0.15 mW zener diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
CZRUR3V0B-HFZener diode, ComchipZener diodeNot recordedComchip
- What it is
- Zener diode
- Maker
- Comchip
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 3 V 0.15 mW zener diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
EMI4184MUESD protection diode, onsemiESD protection diodeNot recordedonsemi
- What it is
- ESD protection diode
- Maker
- onsemi
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Common Mode Filter with ESD Protection
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
NUF2114MNESD protection diode, onsemiESD protection diodeNot recordedonsemi
- What it is
- ESD protection diode
- Maker
- onsemi
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 2 Line Audio EMI Filter with ESD Protection
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
SDB14HSSchottky diode, DiotecSchottky diodeNot recordedDiotec
- What it is
- Schottky diode
- Maker
- Diotec
- Package
- Not recorded
- Pins
- Not recorded
- Details
- SMD Low Barrier Schottky Rectifier Diodes
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
TSD012-368WTSchottky diode, Taitron ComponentsSchottky diodeNot recordedTaitron Components
- What it is
- Schottky diode
- Maker
- Taitron Components
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Schottky Barrier Diodes (Two Terminals)
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
VS8V0UA1LBTVS 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.
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.
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.
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.
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.
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.
Codes that begin with U4
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 22 more parts.
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