SMD code A4 in SOT-563
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.
2 parts in SOT-563 are printed A4
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.
BAV70DXV6SOT-563Switching diode, 6 pins, onsemiSwitching diode6 pinsonsemi
- What it is
- Switching diode
- Maker
- onsemi
- Package
- SOT-563
- Pins
- 6
- Details
- Monolithic Dual Switching Diode Common Cathode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
NSVBAV70DXV6SOT-563Switching diode, 6 pins, onsemiSwitching diode6 pinsonsemi
- What it is
- Switching diode
- Maker
- onsemi
- Package
- SOT-563
- Pins
- 6
- Details
- Monolithic Dual Switching Diode Common Cathode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
13 more parts have no package on record. Nothing rules them out, so they stay.
BZX884B3V3Zener diode, Good-ArkZener diodeNot recordedGood-Ark
- What it is
- Zener diode
- Maker
- Good-Ark
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Zener diode, VZ 3.3 V, 0.25 W
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
EMA4Digital transistor (resistors built in), ROHMDigital transistor (resistors built in)Not recordedROHM
- What it is
- Digital transistor (resistors built in)
- Maker
- ROHM
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Emitter common(dual digital transistor)
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Digital transistor.
FM4004-LRectifier, Formosa MicrosemiRectifierNot recordedFormosa Microsemi
- What it is
- Rectifier
- Maker
- Formosa Microsemi
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Rectifier diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
FM4004-L-Q1Rectifier, Formosa MicrosemiRectifierNot recordedFormosa Microsemi
- What it is
- Rectifier
- Maker
- Formosa Microsemi
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Rectifier diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
FM4004-MHRectifier, Formosa MicrosemiRectifierNot recordedFormosa Microsemi
- What it is
- Rectifier
- Maker
- Formosa Microsemi
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Rectifier diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
FM4004-MH-Q1Rectifier, Formosa MicrosemiRectifierNot recordedFormosa Microsemi
- What it is
- Rectifier
- Maker
- Formosa Microsemi
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Rectifier diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
FM4004-MSRectifier, Formosa MicrosemiRectifierNot recordedFormosa Microsemi
- What it is
- Rectifier
- Maker
- Formosa Microsemi
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Rectifier diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
FM4004-MS-Q1Rectifier, Formosa MicrosemiRectifierNot recordedFormosa Microsemi
- What it is
- Rectifier
- Maker
- Formosa Microsemi
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Rectifier diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
FM4004-MSTRectifier, Formosa MicrosemiRectifierNot recordedFormosa Microsemi
- What it is
- Rectifier
- Maker
- Formosa Microsemi
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Rectifier diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
FM4004-MST-Q1Rectifier, Formosa MicrosemiRectifierNot recordedFormosa Microsemi
- What it is
- Rectifier
- Maker
- Formosa Microsemi
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Rectifier diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
FM4004-SFRectifier, Formosa MicrosemiRectifierNot recordedFormosa Microsemi
- What it is
- Rectifier
- Maker
- Formosa Microsemi
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Rectifier diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
FM4004-SF-Q1Rectifier, Formosa MicrosemiRectifierNot recordedFormosa Microsemi
- What it is
- Rectifier
- Maker
- Formosa Microsemi
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Rectifier diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
HFCN-4400+RF filter, Mini-CircuitsRF filterNot recordedMini-Circuits
- What it is
- RF filter
- Maker
- Mini-Circuits
- Package
- Not recorded
- Pins
- Not recorded
- Details
- LTCC filter, 5000-10100 MHz
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: This part.
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.
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.
Digital transistor
Ohms range, part lifted. The datasheet gives the built-in resistors: R1 in series with the base, R2 from base to emitter.
Working, it reads
Base to emitter reads about R1 plus R2 either way round, about 20 kΩ on a 10 k and 10 k part, give or take their wide tolerance. Collector to emitter reads open. A part with no R2 reads a junction behind R1 one way instead.
Dead, it reads
- Collector to emitter the same both ways, near 0 Ω with a continuous beep: shorted.
- From the base, open or far above R1 plus R2: R1 has failed. Static damage shows here most often.
- Base to emitter near 0 Ω: failed short.
- 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:
- The readings depend on the resistor values, so an identical part elsewhere on the board is the surest reference. Measure it the same way.
- Watch for:
- On the diode range a good part with 10 kΩ resistors reads open on every pair, so a good part looks dead there. Use the ohms range.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
This part
Diode range and ohms range, part lifted.
Working, it reads
Depends on what it is. The datasheet, or an identical part, says.
Dead, it reads
- Between two pins, the same reading both ways, near 0 V with a continuous beep: shorted.
- Open between every pair of pins: failed open, or a part that reads open when working.
- 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.
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 A4
For a marking with its end worn or burnt off. Each code has a page of its own.
- A413
- A4990D1
- A433
- A474
- A49921
- A49961
- A401
- A421
- A441
- A452
- A462
- A482
- A492
- A4C1
- A4F2
- A47A2
- A4X1
- A40A2
- A40B2
- A41A1
- A41B1
- A42A1
- A42B1
- A43A1
- A43B1
- A44A1
- A44B1
- A45A1
- A45B1
- A46A1
- A46B1
- A47B1
- A48A1
- A48B1
- A49A1
- A49B1
- A4543
- A4563
- A4583
Codes not listed here are printed on 31 more parts.
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