SMD code ZQ-
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.
66 parts are printed ZQ-
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.
SMAJ440GSMATVS diode, 2 pins, First SemiconductorTVS diodeSMA2 pinsFirst Semiconductor
- What it is
- TVS diode
- Maker
- First Semiconductor
- Package
- SMA
- Pins
- 2
- Details
- Transient voltage supressor: Vrwm=440V, Vbr=489..602.8V, Ipp=0.5A, 400W(1ms)
- Source
- Published code list
Is it dead? The meter test is below: TVS or ESD protection diode.
TPSMA20ASMATVS diode, 2 pins, Fagor ElectronicaTVS diodeSMA2 pinsFagor Electronica
- What it is
- TVS diode
- Maker
- Fagor Electronica
- Package
- SMA
- Pins
- 2
- Source
- Published code list
Is it dead? The meter test is below: TVS or ESD protection diode.
TV04A750KBSMA2 pins, ComchipNot recordedSMA2 pinsComchip
- What it is
- Not recorded
- Maker
- Comchip
- Package
- SMA
- Pins
- 2
- Details
- TVS: 75V, 10%, 3A, 400W(1ms), Bidirectional
- Source
- Published code list
Is it dead? The meter test is below: TVS or ESD protection diode.
TV04A750KB-GSMATVS diode, 2 pins, ComchipTVS diodeSMA2 pinsComchip
- What it is
- TVS diode
- Maker
- Comchip
- Package
- SMA
- Pins
- 2
- Details
- Transient voltage supressor: Vrwm=75.0V, Vbr=83.30..102.0V, Ipp=2.99A, 400W(1ms), Bidir.
- Source
- Published code list
Is it dead? The meter test is below: TVS or ESD protection diode.
2 more parts have no package on record
TSZL52C16Zener diode, Taiwan SemiconductorZener diodeNot recordedNot recordedTaiwan Semiconductor
- What it is
- Zener diode
- Maker
- Taiwan Semiconductor
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Zener diode: 15.20..16.80V, Izt=5mA, Zzt=40, 200mW
- Source
- Published code list
Is it dead? The meter test is below: Zener diode.
TSZU52C16Zener diode, Taiwan SemiconductorZener diodeNot recordedNot recordedTaiwan Semiconductor
- What it is
- Zener diode
- Maker
- Taiwan Semiconductor
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Zener diode: 15.20..16.80V, Izt=5mA, Zzt=40, 150mW
- Source
- Published code list
Is it dead? The meter test is below: Zener 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.
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.
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