SMD code T03 in SOT-23
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.
4 parts in SOT-23 are printed T03
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.
SOT03CSOT-23ESD protection diode, Galaxy MicroelectronicsESD protection diodeGalaxy Microelectronics
- What it is
- ESD protection diode
- Maker
- Galaxy Microelectronics
- Package
- SOT-23
- Pins
- 3
- Details
- 3V, 150W, Surface Mount TVS
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
TSOT03CSOT-23ESD protection diode, Galaxy MicroelectronicsESD protection diodeGalaxy Microelectronics
- What it is
- ESD protection diode
- Maker
- Galaxy Microelectronics
- Package
- SOT-23
- Pins
- 3
- Details
- 3V, 150W, Surface Mount TVS
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
PDTA114ETSOT-23Digital transistor (PNP, resistors built in), NXPDigital transistor (PNP, resistors built in)NXP
- What it is
- Digital transistor (PNP, resistors built in)
- Maker
- NXP
- Package
- SOT-23
- Pins
- 3
- Details
- 50 V, 100 mA PNP resistor-equipped transistor; R1 = 10 kOhm, R2 = 10 kOhm
- Source
- Published code list
Is it dead? The meter test is below: Digital transistor.
TN2460TSOT-23VishayNot recordedVishay
- What it is
- Not recorded
- Maker
- Vishay
- Package
- SOT-23
- Pins
- 3
- Details
- equivalent TN2460L
- Source
- Published code list
Is it dead? The meter test is below: This part.
1 more part has no package on record. Nothing rules it out, so it stays.
QST3Dual PNP transistor, ROHMDual PNP transistorROHM
- What it is
- Dual PNP transistor
- Maker
- ROHM
- Package
- Not recorded
- Pins
- Not recorded
- Source
- Published code list
Is it dead? The meter test is below: PNP transistor pair.
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.
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.
This part
Diode range and ohms range, part lifted.
Working, it reads
Depends on what it is. The datasheet, or an identical part, says.
Dead, it reads
- Between two pins, the same reading both ways, near 0 V with a continuous beep: shorted.
- Open between every pair of pins: failed open, or a part that reads open when working.
- 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.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
PNP transistor pair
Diode range, part lifted. Test each transistor on its own pins, as the datasheet's pinout gives them.
Working, it reads
Black probe on the base reads about 0.6 to 0.75 V to the emitter and to the collector, and open the other way round. Collector to emitter reads open both ways.
Dead, it reads
- Collector to emitter the same both ways, near 0 V with a continuous beep: shorted. The commonest failure.
- The base the same both ways to another pin, near 0 V or a middling value: a shorted junction.
- Only one junction reads, or none: a junction has failed open. It then looks like a diode.
- A reading the wrong way round, where it should be open: 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 pair of diodes with a common pin reads just like a transistor, and some transistors carry a built-in diode or resistor. The datasheet says which.
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 T03
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 T03
For a marking with its end worn or burnt off. Each code has a page of its own.
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