SMD code U3-
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.
98 parts are printed U3-
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.
BZT52B62SOD-123Zener diode, 2 pins, VishayZener diodeSOD-1232 pinsVishay
- What it is
- Zener diode
- Maker
- Vishay
- Package
- SOD-123
- Pins
- 2
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
BZT52B62-GSOD-123Zener diode, 2 pins, VishayZener diodeSOD-1232 pinsVishay
- What it is
- Zener diode
- Maker
- Vishay
- Package
- SOD-123
- Pins
- 2
- Details
- 5262 V Zener diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
BZX84J-C2V4SOD-323Zener diode, 2 pins, NexperiaZener diodeSOD-3232 pinsNexperia
- What it is
- Zener diode
- Maker
- Nexperia
- Package
- SOD-323
- Pins
- 2
- Pinout
- 1 cathode
- 2 anode
- Details
- 2.4 V approx. ±5% voltage regulator (Zener) diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
CZRF2V7B-HFSOD-323Zener diode, 2 pins, ComchipZener diodeSOD-3232 pinsComchip
- What it is
- Zener diode
- Maker
- Comchip
- Package
- SOD-323
- Pins
- 2
- Details
- 2.7 V 0.2 mW zener diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
ES05MUCSOT-883ESD protection diode, 3 pins, ETEKESD protection diodeSOT-8833 pinsETEK
- What it is
- ESD protection diode
- Maker
- ETEK
- Package
- SOT-883
- Pins
- 3
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
ESDB12CSOT-23ESD protection diode, 3 pins, DiotecESD protection diodeSOT-233 pinsDiotec
- What it is
- ESD protection diode
- Maker
- Diotec
- Package
- SOT-23
- Pins
- 3
- Details
- ESD Protection Diodes in SMD
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
GBLLC03SOD-323ESD protection diode, 2 pins, ProTek DevicesESD protection diodeSOD-3232 pinsProTek Devices
- What it is
- ESD protection diode
- Maker
- ProTek Devices
- Package
- SOD-323
- Pins
- 2
- Details
- 200 Watt Ultra Low Capacitance TVS Array
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
8 more parts have no package on record
ACZRQC2V7B-HFZener diode, ComchipZener diodeNot recordedNot recordedComchip
- What it is
- Zener diode
- Maker
- Comchip
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 2.7 V 0.125 mW zener diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
ACZRUC2V7B-HFZener diode, ComchipZener diodeNot recordedNot recordedComchip
- What it is
- Zener diode
- Maker
- Comchip
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 2.77 V 0.15 mW zener diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
BRESD3V3X1C2ZAESD protection diode, Blue RocketESD protection diodeNot recordedNot recordedBlue Rocket
- What it is
- ESD protection diode
- Maker
- Blue Rocket
- Package
- Not recorded
- Pins
- Not recorded
- Details
- ESD protection diode, bidirectional
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
CZRFR2V7B-HFZener diode, ComchipZener diodeNot recordedNot recordedComchip
- What it is
- Zener diode
- Maker
- Comchip
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 2.7 V 0.2 mW zener diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
CZRQC2V7B-HFZener diode, ComchipZener diodeNot recordedNot recordedComchip
- What it is
- Zener diode
- Maker
- Comchip
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 2.7 V 0.125 mW zener diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
CZRU2V7B-HFZener diode, ComchipZener diodeNot recordedNot recordedComchip
- What it is
- Zener diode
- Maker
- Comchip
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 2.7 V 0.15 mW zener diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
CZRUR2V7B-HFZener diode, ComchipZener diodeNot recordedNot recordedComchip
- What it is
- Zener diode
- Maker
- Comchip
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 27 V 0.15 mW zener diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
EMI4183MUESD protection diode, onsemiESD protection diodeNot recordedNot 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.
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.
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.
Printed with a code easy to misread as U3-
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 U3-
For a marking with its end worn or burnt off. Each code has a page of its own.
- U3J3
- U3AB1
- U3BB1
- U3DB1
- U3GB1
- U3JB1
- U3KB1
- U3MB1
- U3212
- U3314
- U3416
- U30C2
- U31C2
- U32C2
- U33C2
- U34C2
- U35C2
- U36C2
- U37C2
- U38C2
- U39C2
- U30N2
- U31N2
- U32N2
- U33N2
- U34N2
- U35N2
- U36N2
- U37N2
- U38N2
- U39N2
- U30P2
- U31P2
- U32P2
- U33P2
- U34P2
- U35P2
- U36P2
- U37P2
- U38P2
- U39P2
- U30CP2
- U31CP2
- U32CP2
Codes not listed here are printed on 307 more parts.
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