SMD code Y2d
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.
The last letter, d, is lower case, which on NXP and Philips parts is a date or factory code, so it was set aside and Y2 was searched.
111 parts are printed Y2d
Not sure which one you have?
Answer up to 4 quick questions and these 50 parts are ranked, with a meter test that settles it. It works on a dead part too.
BZX584C12SOD-523Zener diode, 2 pins, Galaxy MicroelectronicsZener diodeSOD-5232 pinsGalaxy Microelectronics
- What it is
- Zener diode
- Maker
- Galaxy Microelectronics
- Package
- SOD-523
- Pins
- 2
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
BZX584C12-MSSOD-523Zener diode, 2 pins, MSKSEMIZener diodeSOD-5232 pinsMSKSEMI
- What it is
- Zener diode
- Maker
- MSKSEMI
- Package
- SOD-523
- Pins
- 2
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
BZX584C12AUSOD-523Zener diode, 2 pins, JieJieZener diodeSOD-5232 pinsJieJie
- What it is
- Zener diode
- Maker
- JieJie
- Package
- SOD-523
- Pins
- 2
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
BZX784C30SOD-723Zener diode, 2 pins, SeCoSZener diodeSOD-7232 pinsSeCoS
- What it is
- Zener diode
- Maker
- SeCoS
- Package
- SOD-723
- Pins
- 2
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
CZRH584C12-HFSOD-523Zener diode, 2 pins, ComchipZener diodeSOD-5232 pinsComchip
- What it is
- Zener diode
- Maker
- Comchip
- Package
- SOD-523
- Pins
- 2
- Details
- 12 V 0.2 mW zener diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
DMBT8550SOT-23PNP transistor, 3 pins, DC ComponentsPNP transistorSOT-233 pinsDC Components
- What it is
- PNP transistor
- Maker
- DC Components
- Package
- SOT-23
- Pins
- 3
- Details
- PNP bipolar transistor
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: PNP transistor.
FS8550SOT-23NPN transistor, 3 pins, Formosa MicrosemiNPN transistorSOT-233 pinsFormosa Microsemi
- What it is
- NPN transistor
- Maker
- Formosa Microsemi
- Package
- SOT-23
- Pins
- 3
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: NPN transistor.
GSS8550SOT-23PNP transistor, 3 pins, Good-ArkPNP transistorSOT-233 pinsGood-Ark
- What it is
- PNP transistor
- Maker
- Good-Ark
- Package
- SOT-23
- Pins
- 3
- Details
- PNP transistor, 25 V, 1.5 A
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: PNP transistor.
LBZX84C12LT1GSOT-23Zener diode, 3 pins, LRCZener diodeSOT-233 pinsLRC
- What it is
- Zener diode
- Maker
- LRC
- Package
- SOT-23
- Pins
- 3
- Details
- Zener diode, VZ Min 11.4 V, VZ Nom 12 V, VZ Max 12.7 V
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
MM3Z36BWSOD-323Zener diode, 2 pins, YFWZener diodeSOD-3232 pinsYFW
- What it is
- Zener diode
- Maker
- YFW
- Package
- SOD-323
- Pins
- 2
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
MM5Z12V-CSOD-523Zener diode, 2 pins, SeCoSZener diodeSOD-5232 pinsSeCoS
- What it is
- Zener diode
- Maker
- SeCoS
- Package
- SOD-523
- Pins
- 2
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
MMBT1781-RSOT-23NPN transistor, 3 pins, Good-ArkNPN transistorSOT-233 pinsGood-Ark
- What it is
- NPN transistor
- Maker
- Good-Ark
- Package
- SOT-23
- Pins
- 3
- Details
- NPN transistor, 32 V, 0.8 A
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: NPN transistor.
MMBTSD123SOT-23Transistor, 3 pins, YFWTransistorSOT-233 pinsYFW
- What it is
- Transistor
- Maker
- YFW
- Package
- SOT-23
- Pins
- 3
- Details
- Bipolar transistor
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Bipolar transistor.
2 more parts have no package on record
KRC836EDigital transistor (NPN, resistors built in), KECDigital transistor (NPN, resistors built in)Not recordedNot recordedKEC
- What it is
- Digital transistor (NPN, resistors built in)
- Maker
- KEC
- Package
- Not recorded
- Pins
- Not recorded
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Digital transistor.
KRC836UDigital transistor (NPN, resistors built in), KECDigital transistor (NPN, resistors built in)Not recordedNot recordedKEC
- What it is
- Digital transistor (NPN, resistors built in)
- Maker
- KEC
- Package
- Not recorded
- Pins
- Not recorded
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Digital transistor.
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.
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.
PNP transistor
Diode range, part lifted or its base leg off the pad.
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.
NPN transistor
Diode range, part lifted or its base leg off the pad.
Working, it reads
Red 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.
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.
Bipolar transistor
Diode range, part lifted or its base leg off the pad.
Working, it reads
From the base, one probe colour 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.
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