SMD code 3W
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.
20 parts are printed 3W
Not sure which one you have?
Answer up to 4 quick questions and these 20 parts are ranked, with a meter test that settles it. It works on a dead part too.
RP112K291DDFNLDO regulator, RicohLDO regulatorDFNNot recordedRicoh
- What it is
- LDO regulator
- Maker
- Ricoh
- Package
- DFN
- Pins
- Not recorded
- Details
- Linear voltage regulator IC: LDO, 2.9V±1%, 150mA, +CE, CL
- Source
- Published code list
Is it dead? The meter test is below: Voltage regulator.
RP173K291BDFNLDO regulator, RicohLDO regulatorDFNNot recordedRicoh
- What it is
- LDO regulator
- Maker
- Ricoh
- Package
- DFN
- Pins
- Not recorded
- Details
- Linear voltage regulator IC: LDO, 2.9V±1%, 150mA, +CE
- Source
- Published code list
Is it dead? The meter test is below: Voltage regulator.
RQ5RW39CASOT-1434 pins, Nisshinbo Micro DevicesNot recordedSOT-1434 pinsNisshinbo Micro Devices
- What it is
- Not recorded
- Maker
- Nisshinbo Micro Devices
- Package
- SOT-143
- Pins
- 4
- Details
- VR-IC: LDO, 3,9V±2%, 150mA
- Source
- Published code list
Is it dead? The meter test is below: Voltage regulator.
RT9728CHGQWDFNLoad switch, 6 pins, RichtekLoad switchDFN6 pinsRichtek
- What it is
- Load switch
- Maker
- Richtek
- Package
- DFN
- Pins
- 6
- Details
- Power switch
- Source
- Published code list
Is it dead? The meter test is below: Load switch.
TDZ16JSOD-323Zener diode, 2 pins, NXPZener diodeSOD-3232 pinsNXP
- What it is
- Zener diode
- Maker
- NXP
- Package
- SOD-323
- Pins
- 2
- Details
- Zener diode: 15.70..16.30V, Izt=5mA, Zzt=20, 500mW
- 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.
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.
Load switch
Voltage, board powered, black probe on ground.
Working, it reads
Switched on, the output pin sits at the input voltage. Switched off, it sits near 0 V.
Dead, it reads
- Output at the input voltage while switched off: the pass element has shorted.
- Input present and switched on, no output: failed open, or shut down into a shorted load. Power off and measure output to ground.
- On the board:
- An output near 0 Ω to ground is usually the load. Lift the output pin to see which.
- 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 pinout and whether the enable is active high or low differ between parts. The datasheet gives both.
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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