SMD code search: identify a part by its marking
316 MΩ resistor. 2 parts are printed 3166. 9 printed with a similar-looking code.
3166 on a chip resistor
316 MΩ
316 MΩ resistor, 1%
316 followed by 6 zeros. Four digits is normally the 1% series.
Check it with a meter
Lift one end and measure across it. A good one reads 316 MΩ within 1%. Measuring it in circuit reads the parallel combination of everything around it, which is almost always lower, never higher: well above 316 MΩ on the board is a fault. Open, or well above 316 MΩ, means it has failed: burnt, cracked or corroded. That does not change what to fit: the marking still says 316 MΩ. A burnt resistor usually means the part it feeds drew too much, so find that before fitting a new one.
On a transistor or diode body (SOT-23, SOT-23-5, SOT-353), 3166 is a part code instead. Those parts are listed below.
2 parts are printed 3166
Not sure which one you have?
Answer up to 4 quick questions and these 2 parts are ranked, with a meter test that settles it. It works on a dead part too.
Analog switch, 5 pins, all Gainsil. What differs:
GS3166-CRSOT-353SOT-353
- What it is
- Analog switch
- Maker
- Gainsil
- Package
- SOT-353
- Pins
- 5
- Source
- Manufacturer datasheet
Is it dead?
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.
GS3166-TRSOT-23-5SOT-23-5
- What it is
- Analog switch
- Maker
- Gainsil
- Package
- SOT-23-5
- Pins
- 5
- Source
- Manufacturer datasheet
Is it dead?
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.
9 more parts are printed with a code easy to misread as 3166
Printed with a code easy to misread
One character differs, and it is one that is easy to confuse under a lamp. The odd one out is marked on each.
AP8853-16Cprinted 316CSOT-23LDO regulator, 3 pins, Anwell SemiconductorLDO regulatorSOT-233 pinsAnwell Semiconductor
Printed 316C on the part. Easy to misread as 3166. Check that character with a loupe before you order anything.
- What it is
- LDO regulator
- Maker
- Anwell Semiconductor
- Package
- SOT-23
- Pins
- 3
- Details
- Linear voltage regulator IC: LDO, 1.6V±2%, 300mA, Pb-free
- Source
- Published code list
Is it dead?
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.
FS8853-16CCprinted 316CSOT-23LDO regulator, 3 pins, Fortune SemiconductorLDO regulatorSOT-233 pinsFortune Semiconductor
Printed 316C on the part. Easy to misread as 3166. Check that character with a loupe before you order anything.
- What it is
- LDO regulator
- Maker
- Fortune Semiconductor
- Package
- SOT-23
- Pins
- 3
- Details
- Linear voltage regulator IC: LDO, 1.6V+35mV, 300mA
- Source
- Published code list
Is it dead?
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.
FS8853-16PCprinted 316CSOT-23LDO regulator, 3 pins, Fortune SemiconductorLDO regulatorSOT-233 pinsFortune Semiconductor
Printed 316C on the part. Easy to misread as 3166. Check that character with a loupe before you order anything.
- What it is
- LDO regulator
- Maker
- Fortune Semiconductor
- Package
- SOT-23
- Pins
- 3
- Details
- Linear voltage regulator IC: LDO, 1.6V+35mV, 300mA, Pb-free
- Source
- Published code list
Is it dead?
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.
U74LVC1G126G-AE5printed 3L6GSOT-23-55 pins, UnisonicNot recordedSOT-23-55 pinsUnisonic
Printed 3L6G on the part. Easy to misread as 3166. Check that character with a loupe before you order anything.
- What it is
- Not recorded
- Maker
- Unisonic
- Package
- SOT-23-5
- Pins
- 5
- Details
- CMOS logic IC: Bus buffer gate with 3-state output, H-free
- Source
- Published code list
Is it dead?
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.
U74LVC1G126G-AF5printed 3L6GSOT-23-55 pins, UnisonicNot recordedSOT-23-55 pinsUnisonic
Printed 3L6G on the part. Easy to misread as 3166. Check that character with a loupe before you order anything.
- What it is
- Not recorded
- Maker
- Unisonic
- Package
- SOT-23-5
- Pins
- 5
- Details
- CMOS logic IC: Bus buffer gate with 3-state output, H-free
- Source
- Published code list
Is it dead?
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.
U74LVC1G126G-AL5printed 3L6GSOT-3535 pins, UnisonicNot recordedSOT-3535 pinsUnisonic
Printed 3L6G on the part. Easy to misread as 3166. Check that character with a loupe before you order anything.
- What it is
- Not recorded
- Maker
- Unisonic
- Package
- SOT-353
- Pins
- 5
- Details
- CMOS logic IC: Bus buffer gate with 3-state output, H-free
- Source
- Published code list
Is it dead?
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.
3 more parts have no package on record
WP3116-CC12Rprinted 316CLoad switch, WayonLoad switchNot recordedNot recordedWayon
Printed 316C on the part. Easy to misread as 3166. Check that character with a loupe before you order anything.
- What it is
- Load switch
- Maker
- Wayon
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Overvoltage protection switch
- Source
- Manufacturer datasheet
Is it dead?
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.
WP3116-CPB2Rprinted 316CLoad switch, WayonLoad switchNot recordedNot recordedWayon
Printed 316C on the part. Easy to misread as 3166. Check that character with a loupe before you order anything.
- What it is
- Load switch
- Maker
- Wayon
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Overvoltage protection switch
- Source
- Manufacturer datasheet
Is it dead?
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.
U74LVC1G126G-K06-14510printed 3L6GUnisonicNot recordedNot recordedNot recordedUnisonic
Printed 3L6G on the part. Easy to misread as 3166. Check that character with a loupe before you order anything.
- What it is
- Not recorded
- Maker
- Unisonic
- Package
- Not recorded
- Pins
- Not recorded
- Details
- CMOS logic IC: Bus buffer gate with 3-state output, H-free
- Source
- Published code list
Is it dead?
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.
1 more part has a code that begins with 3166
Codes that begin with 3166
For a marking with its end worn or burnt off. Each one shows its full printed code.
AP8853-16GCprinted 316CGSOT-23LDO regulator, 3 pins, Anwell SemiconductorLDO regulatorSOT-233 pinsAnwell Semiconductor
Printed 316CG. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.
- What it is
- LDO regulator
- Maker
- Anwell Semiconductor
- Package
- SOT-23
- Pins
- 3
- Details
- Linear voltage regulator IC: LDO, 1.6V±2%, 300mA, H-free
- Source
- Published code list
Is it dead?
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.
Did you find your part?
One code, several parts
Marking codes are not unique. In the standard code book, 6H on a SOT-23 is an NPN transistor, a varicap, an N-channel JFET, two digital transistors, a 3.6 V voltage detector: six parts from five makers. So a search shows the parts we hold under that code and under codes easily misread as it, with only the columns that tell them apart.
- NPN transistor
- Varicap
- N-channel JFET
- Digital transistor ×2
- 3.6 V voltage detector
When more than one is left
Tap Help me choose. Up to 4 quick answers: whether the part has failed, then what separates the parts left. Those get ranked with the reasoning and a test that settles it. That uses one identification: 2 a month are free without an account, and 3 with a free account.
When you cannot read it
Tap the camera in the field. We read the characters, keep the ones we are unsure of, and search every reading. A photo too soft to read is turned back on your phone first; if it is the only one you can get, you can still send it.
Get the app
The same search on your phone, and a camera with a light, zoom and tap to focus for a marking you cannot read. Sign in with your email address to use the same account.
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