SMD code WIs in TSFP-3
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.
The last letter, s, is lower case, which on NXP and Philips parts is a date or factory code, so it was set aside and WI was searched.
1 part in TSFP-3 is printed WIs
Not sure which one you have?
Answer up to 4 quick questions and these 4 parts are ranked, with a meter test that settles it. It works on a dead part too.
BCR158FTSFP-3Digital transistor (PNP, resistors built in), 3 pins, InfineonDigital transistor (PNP, resistors built in)3 pinsInfineon
- What it is
- Digital transistor (PNP, resistors built in)
- Maker
- Infineon
- Package
- TSFP-3
- Pins
- 3
- Details
- Si-pnp-Digi: Sw, 50V, 100mA, 250mW, R1/R2=2.2k/47k, 170MHz
- Source
- Published code list
Is it dead? The meter test is below: Digital transistor.
3 more parts have no package on record. Nothing rules them out, so they stay.
ESDUNJ4V8B1ESD protection diode, JSCJESD protection diodeNot recordedJSCJ
- What it is
- ESD protection diode
- Maker
- JSCJ
- Package
- Not recorded
- Pins
- Not recorded
- Details
- ESD protection diode, VRWM 4.8 V
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
AX5505R50DC-DC converterDC-DC converterNot recordedNot recorded
- What it is
- DC-DC converter
- Maker
- Not recorded
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Micropower VFM Synchronous Step-up DC/DC Converter
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
BCR158L3Digital transistor (PNP, resistors built in), InfineonDigital transistor (PNP, resistors built in)Not recordedInfineon
- What it is
- Digital transistor (PNP, resistors built in)
- Maker
- Infineon
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Si-pnp-Digi: Sw, 50V, 100mA, 250mW, R1/R2=2.2k/47k, 170MHz
- Source
- Published code list
Is it dead? The meter test is below: Digital transistor.
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.
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.
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.
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.
Printed with a code easy to misread as WIs
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 WIs
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 25 more parts.
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