SMD code UN
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.
6 parts are printed UN
Not sure which one you have?
Answer up to 4 quick questions and these 6 parts are ranked, with a meter test that settles it. It works on a dead part too.
BZX84J-C62SOD-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
- 62 V approx. ±5% voltage regulator (Zener) diode
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: Zener diode.
MMFTP2307ASOT-23MOSFET, 3 pins, DiotecMOSFETSOT-233 pinsDiotec
- What it is
- MOSFET
- Maker
- Diotec
- Package
- SOT-23
- Pins
- 3
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: MOSFET.
MMSZ4703SOD-123Zener diode, 2 pins, VishayZener diodeSOD-1232 pinsVishay
- What it is
- Zener diode
- Maker
- Vishay
- Package
- SOD-123
- Pins
- 2
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: Zener diode.
MMSZ4703-GSOD-123Zener diode, 2 pins, VishayZener diodeSOD-1232 pinsVishay
- What it is
- Zener diode
- Maker
- Vishay
- Package
- SOD-123
- Pins
- 2
- Details
- 16 V Zener diode
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: Zener diode.
PZS52C11M1QSOD-882Zener diode, 2 pins, PanjitZener diodeSOD-8822 pinsPanjit
- What it is
- Zener diode
- Maker
- Panjit
- Package
- SOD-882
- Pins
- 2
- Source
- From the manufacturer's datasheet
Is it dead? The meter test is below: Zener diode.
TPS3895ADRYSONVoltage supervisor, 6 pins, Texas InstrumentsVoltage supervisorSON6 pinsTexas Instruments
- What it is
- Voltage supervisor
- Maker
- Texas Instruments
- Package
- SON
- Pins
- 6
- Details
- Single-Channel, Adjustable Voltage Monitor in Ultra-Small Package
- Source
- From the manufacturer's datasheet
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.
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.
MOSFET
Diode range, part lifted. Test drain to source first, then short gate to source and test again.
Working, it reads
One way between drain and source reads about 0.4 to 0.9 V, the body diode, and the other way open. The gate reads open to both other pins.
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.
- No body diode at all: failed open.
- On the board
- the gate usually has a resistor to the source, which reads as that resistor and 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.
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.
Codes that begin with UN
For a marking with its end worn or burnt off. Each code has a page of its own.
Open this in the search to correct a character or try another package.