SMD code SW in SMAF
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.
1 part in SMAF is printed SW
Not sure which one you have?
Answer up to 4 quick questions and these 5 parts are ranked, with a meter test that settles it. It works on a dead part too.
SMAJ200ASMAFTVS diode, Formosa MicrosemiTVS diodeFormosa Microsemi
- What it is
- TVS diode
- Maker
- Formosa Microsemi
- Package
- SMAF
- Pins
- 2
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
4 more parts have no package on record. Nothing rules them out, so they stay.
VS20VUA1VWMTVS diode, ROHMTVS diodeROHM
- What it is
- TVS diode
- Maker
- ROHM
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Transient Voltage Suppressor
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
VS20VUA1VWMTFTVS diode, ROHMTVS diodeROHM
- What it is
- TVS diode
- Maker
- ROHM
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Transient Voltage Suppressor
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
RP131K521ALDO regulator, RicohLDO regulatorRicoh
- What it is
- LDO regulator
- Maker
- Ricoh
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Low Noise 150mA LDO Regulator
- Source
- Published code list
Is it dead? The meter test is below: Voltage regulator.
SM4T100SGS-Thomson MicroelectronicsNot recordedSGS-Thomson Microelectronics
- What it is
- Not recorded
- Maker
- SGS-Thomson Microelectronics
- Package
- Not recorded
- Pins
- Not recorded
- Details
- TVS: 100V, 2,9A, 400W(1ms)
- Source
- Published code list
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.
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.
Voltage regulator
Voltage, board powered, black probe on ground. Then ohms with the power off.
Working, it reads
Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.
Dead, it reads
- Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
- Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
- Power off, input to output near 0 Ω: shorted.
- On the board:
- An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
- Compare:
- The same regulator on another rail or another board shows the right voltages and the right resistances.
- Watch for:
- Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.
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 SW
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 SW
For a marking with its end worn or burnt off. Each code has a page of its own.
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