SMD code search: identify a part by its marking

Not sure which one you have?

Answer up to 4 quick questions and these 18 parts are ranked, with a meter test that settles it. It works on a dead part too.

The only part printed BQLB in our tables

TC1301BQLBVMF

What it is: Not recorded
Maker: Microchip
Package: DFN
Pins: Not recorded
Details: Linear voltage regulator with volatge detector: LDO, Dual out, Vo1/Vo2=1.7V(300mA)/2.2V(150mA)±2.5%, Vdet=2.2V±2.5%, +CE
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.

Was it this one?

Printed with a code easy to misread

These parts are printed with a character that is easy to misread as what you typed. The odd one out is marked on each.

R1154L118Bprinted BQ18DFNLDO regulator, RicohLDO regulatorDFNNot recordedRicoh
Printed BQ18 on the part. Easy to misread as BQLB. Check that character with a loupe before you order anything.
What it is
LDO regulator
Maker
Ricoh
Package
DFN
Pins
Not recorded
Details
Linear voltage regulator IC: LDO, 11.8V±2%, 150mA, +CE
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.
R1161D122B5printed B01BSONNisshinbo Micro DevicesNot recordedSONNot recordedNisshinbo Micro Devices
Printed B01B on the part. Easy to misread as BQLB. Check that character with a loupe before you order anything.
What it is
Not recorded
Maker
Nisshinbo Micro Devices
Package
SON
Pins
Not recorded
Details
VR-IC: LDO, CE, 1.25V±2%, 350mA
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.
R1516H018Bprinted B018SOT-89-5LDO regulator, 5 pins, RicohLDO regulatorSOT-89-55 pinsRicoh
Printed B018 on the part. Easy to misread as BQLB. Check that character with a loupe before you order anything.
What it is
LDO regulator
Maker
Ricoh
Package
SOT-89-5
Pins
5
Details
Linear voltage regulator IC: LDO, 1.8V±1%, 150mA, +CE
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.
R3117Q242Cprinted B018SOT-23-5Voltage supervisor, 5 pins, RicohVoltage supervisorSOT-23-55 pinsRicoh
Printed B018 on the part. Easy to misread as BQLB. Check that character with a loupe before you order anything.
What it is
Voltage supervisor
Maker
Ricoh
Package
SOT-23-5
Pins
5
Details
Voltage detector IC: 2.4V±1%, -Reset PPO, Sense
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.
RP153L018Eprinted BD18DFNLDO regulator, RicohLDO regulatorDFNNot recordedRicoh
Printed BD18 on the part. Easy to misread as BQLB. Check that character with a loupe before you order anything.
What it is
LDO regulator
Maker
Ricoh
Package
DFN
Pins
Not recorded
Details
Linear voltage regulator IC: LDO, Dual out, Vout1/Vout2=1.8V/1.8V±1%, 150mA, +CE
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.
STBB018printed B018SMATVS diode, 2 pins, EIC SemiconductorTVS diodeSMA2 pinsEIC Semiconductor
Printed B018 on the part. Easy to misread as BQLB. Check that character with a loupe before you order anything.
What it is
TVS diode
Maker
EIC Semiconductor
Package
SMA
Pins
2
Details
TVS: 17.1..19.8V, 16A, 400W(1ms), Bidirectional
Source
Published code list
Is it dead?
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.
STUB018printed B018SMATVS diode, 2 pins, EIC SemiconductorTVS diodeSMA2 pinsEIC Semiconductor
Printed B018 on the part. Easy to misread as BQLB. Check that character with a loupe before you order anything.
What it is
TVS diode
Maker
EIC Semiconductor
Package
SMA
Pins
2
Details
TVS: 17.1..19.8V, 16A, 400W(1ms)
Source
Published code list
Is it dead?
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.
TC1301BDIBVMFprinted BDIBDFNMicrochipNot recordedDFNNot recordedMicrochip
Printed BDIB on the part. Easy to misread as BQLB. Check that character with a loupe before you order anything.
What it is
Not recorded
Maker
Microchip
Package
DFN
Pins
Not recorded
Details
Linear voltage regulator with volatge detector: LDO, Dual out, Vo1/Vo2=3.0V(300mA)/2.5V(150mA)±2.5%, Vdet=2.2V±2.5%, +CE
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.
TC1301BDLBVMFprinted BDLBDFNMicrochipNot recordedDFNNot recordedMicrochip
Printed BDLB on the part. Easy to misread as BQLB. Check that character with a loupe before you order anything.
What it is
Not recorded
Maker
Microchip
Package
DFN
Pins
Not recorded
Details
Linear voltage regulator with volatge detector: LDO, Dual out, Vo1/Vo2=3.0V(300mA)/2.2V(150mA)±2.5%, Vdet=2.2V±2.5%, +CE
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.
TC1301BOIBVMFprinted BOIBDFNMicrochipNot recordedDFNNot recordedMicrochip
Printed BOIB on the part. Easy to misread as BQLB. Check that character with a loupe before you order anything.
What it is
Not recorded
Maker
Microchip
Package
DFN
Pins
Not recorded
Details
Linear voltage regulator with volatge detector: LDO, Dual out, Vo1/Vo2=1.9V(300mA)/2.5V(150mA)±2.5%, Vdet=2.2V±2.5%, +CE
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.
TC1301BOLBVMFprinted BOLBDFNMicrochipNot recordedDFNNot recordedMicrochip
Printed BOLB on the part. Easy to misread as BQLB. Check that character with a loupe before you order anything.
What it is
Not recorded
Maker
Microchip
Package
DFN
Pins
Not recorded
Details
Linear voltage regulator with volatge detector: LDO, Dual out, Vo1/Vo2=1.9V(300mA)/2.2V(150mA)±2.5%, Vdet=2.2V±2.5%, +CE
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.
TC1301BQIBVMFprinted BQIBDFNMicrochipNot recordedDFNNot recordedMicrochip
Printed BQIB on the part. Easy to misread as BQLB. Check that character with a loupe before you order anything.
What it is
Not recorded
Maker
Microchip
Package
DFN
Pins
Not recorded
Details
Linear voltage regulator with volatge detector: LDO, Dual out, Vo1/Vo2=1.7V(300mA)/2.5V(150mA)±2.5%, Vdet=2.2V±2.5%, +CE
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.
5 more parts have no package on record
- R1172S181B5printed B01BNisshinbo Micro DevicesNot recordedNot recordedNot recordedNisshinbo Micro Devices
  Printed B01B on the part. Easy to misread as BQLB. Check that character with a loupe before you order anything.
  What it is
  Not recorded
  Maker
  Nisshinbo Micro Devices
  Package
  Not recorded
  Pins
  Not recorded
  Details
  VR-IC: LDO, CE, 1.85V±2%, 1A
  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.
- R1525S025Bprinted B01BRicohNot recordedNot recordedNot recordedRicoh
  Printed B01B on the part. Easy to misread as BQLB. Check that character with a loupe before you order anything.
  What it is
  Not recorded
  Maker
  Ricoh
  Package
  Not recorded
  Pins
  Not recorded
  Details
  Linear voltage regulator IC: 2.5V±0.6%, 200mA, +CE
  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.
- XC9276D018ER-Gprinted B018DC-DC converter, TorexDC-DC converterNot recordedNot recordedTorex
  Printed B018 on the part. Easy to misread as BQLB. Check that character with a loupe before you order anything.
  What it is
  DC-DC converter
  Maker
  Torex
  Package
  Not recorded
  Pins
  Not recorded
  Details
  DC/DC voltage converter IC: PFM, st-dwn, Vout=0.6(Vset=Low) or Vout=1.5V(Vset=High), +CE, CL
  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.
- XC9276D018MR-Gprinted B018DC-DC converter, TorexDC-DC converterNot recordedNot recordedTorex
  Printed B018 on the part. Easy to misread as BQLB. Check that character with a loupe before you order anything.
  What it is
  DC-DC converter
  Maker
  Torex
  Package
  Not recorded
  Pins
  Not recorded
  Details
  DC/DC voltage converter IC: PFM, st-dwn, Vout=0.6(Vset=Low) or Vout=1.5V(Vset=High), +CE, CL
  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.
- XC9276D0180R-Gprinted B018DC-DC converter, TorexDC-DC converterNot recordedNot recordedTorex
  Printed B018 on the part. Easy to misread as BQLB. Check that character with a loupe before you order anything.
  What it is
  DC-DC converter
  Maker
  Torex
  Package
  Not recorded
  Pins
  Not recorded
  Details
  DC/DC voltage converter IC: PFM, st-dwn, Vout=0.6(Vset=Low) or Vout=1.5V(Vset=High), +CE, CL
  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.

4 more parts have codes that begin with BQLB

Codes that begin with BQLB

For a marking with its end worn or burnt off. Each one shows its full printed code.

SMBJ18Aprinted B018AJSMBTVS diode, 2 pins, WeEn SemiconductorsTVS diodeSMB2 pinsWeEn Semiconductors
Printed B018AJ. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.
What it is
TVS diode
Maker
WeEn Semiconductors
Package
SMB
Pins
2
Source
Manufacturer datasheet
Is it dead?
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.
Datasheetfor SMBJ18A, opens in a new tab
SMBJ18CAprinted B018CJSMBTVS diode, 2 pins, WeEn SemiconductorsTVS diodeSMB2 pinsWeEn Semiconductors
Printed B018CJ. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.
What it is
TVS diode
Maker
WeEn Semiconductors
Package
SMB
Pins
2
Source
Published code list
Is it dead?
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.
Datasheetfor SMBJ18CA, opens in a new tab
XC9216D18CDprinted BD18CUSP-6BDC-DC converter, 6 pins, TorexDC-DC converterUSP-6B6 pinsTorex
Printed BD18C. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.
What it is
DC-DC converter
Maker
Torex
Package
USP-6B
Pins
6
Details
DC/DC voltage converter IC: PWM/PFM st-dwn, 1.8V±2%, 500mA, 1.2MHz, -CE, PUR
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.
XC9216D186Dprinted BD186USP-6BDC-DC converter, 6 pins, TorexDC-DC converterUSP-6B6 pinsTorex
Printed BD186. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.
What it is
DC-DC converter
Maker
Torex
Package
USP-6B
Pins
6
Details
DC/DC voltage converter IC: PWM/PFM st-dwn, 1.8V±2%, 500mA, 600KHz, -CE, PUR
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.

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.

6Hon a SOT-23, in the code book

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.

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SMD code search: identify a part by its marking

What’s printed on it?

TC1301BQLBVMF

Is it dead?

Printed with a code easy to misread

Is it dead?

Is it dead?

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Is it dead?

Is it dead?

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Is it dead?

Is it dead?

Is it dead?

Is it dead?

Is it dead?

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Is it dead?

Is it dead?

Is it dead?

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Is it dead?

Codes that begin with BQLB

Is it dead?

Is it dead?

Is it dead?

Is it dead?

Did you find your part?

One code, several parts

When more than one is left

When you cannot read it

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