SMD code 40D
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.
40D on a chip resistor
255 kΩ
255 kΩ resistor, 1%
EIA-96 precision code: 40 selects 2.55 from the E96 series and D multiplies by 100000. These are 1% parts.
Check it with a meter
Lift one end and measure across it. A good one reads 255 kΩ within 1%. Measuring it in circuit reads the parallel combination of everything around it, which is almost always lower, never higher: well above 255 kΩ on the board is a fault. Open, or well above 255 kΩ, means it has failed: burnt, cracked or corroded. That does not change what to fit: the marking still says 255 kΩ. 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-23-5, SOT-23, USP-6C), 40D is a part code instead. Those parts are listed below.
8 parts are printed 40D
Not sure which one you have?
Answer up to 4 quick questions and these 8 parts are ranked, with a meter test that settles it. It works on a dead part too.
AAT60040D-S2SOT-23Voltage supervisor, 3 pins, Advanced Analog TechnologyVoltage supervisorSOT-233 pinsAdvanced Analog Technology
- What it is
- Voltage supervisor
- Maker
- Advanced Analog Technology
- Package
- SOT-23
- Pins
- 3
- Details
- Voltage detector IC: 4.0V±1%, -Reset PPO
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
AAT60040D-S5SOT-23-5Voltage supervisor, 5 pins, Advanced Analog TechnologyVoltage supervisorSOT-23-55 pinsAdvanced Analog Technology
- What it is
- Voltage supervisor
- Maker
- Advanced Analog Technology
- Package
- SOT-23-5
- Pins
- 5
- Details
- Voltage detector IC: 4.0V±1%, -Reset PPO
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
AAT60040D-S15SOT-143Voltage supervisor, 4 pins, Advanced Analog TechnologyVoltage supervisorSOT-1434 pinsAdvanced Analog Technology
- What it is
- Voltage supervisor
- Maker
- Advanced Analog Technology
- Package
- SOT-143
- Pins
- 4
- Details
- Voltage detector IC: 4.0V±1%, -Reset PPO
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
AAT60040D-S16SOT-89Voltage supervisor, 3 pins, Advanced Analog TechnologyVoltage supervisorSOT-893 pinsAdvanced Analog Technology
- What it is
- Voltage supervisor
- Maker
- Advanced Analog Technology
- Package
- SOT-89
- Pins
- 3
- Details
- Voltage detector IC: 4.0V±1%, -Reset PPO
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
P4SMAFJ40CASMAFTVS diode, 2 pins, Dongguan You Feng Wei ElectronicsTVS diodeSMAF2 pinsDongguan You Feng Wei Electronics
- What it is
- TVS diode
- Maker
- Dongguan You Feng Wei Electronics
- Package
- SMAF
- Pins
- 2
- Details
- Transient voltage supressor: Vrwm=40V, Vbr=44.4..51.1V, Ipp=6.2A, 400W(1ms), Bidir.
- Source
- Published code list
Is it dead? The meter test is below: TVS or ESD protection diode.
P4SMAJ40CASMA2 pins, YeashinNot recordedSMA2 pinsYeashin
- What it is
- Not recorded
- Maker
- Yeashin
- Package
- SMA
- Pins
- 2
- Details
- TVS: 40V, 6.2A, 400W(1ms), Bidirectional
- Source
- Published code list
Is it dead? The meter test is below: TVS or ESD protection diode.
P4SMFJ40CASOD-123FTVS diode, 2 pins, YeashinTVS diodeSOD-123F2 pinsYeashin
- What it is
- TVS diode
- Maker
- Yeashin
- Package
- SOD-123F
- Pins
- 2
- Details
- Transient voltage supressor: Vrwm=40V, Ipp=6.2A, 400W (1ms), Bidir.
- Source
- Published code list
Is it dead? The meter test is below: TVS or ESD protection diode.
XC6105A144MRSOT-23-5Voltage supervisor, 5 pins, TorexVoltage supervisorSOT-23-55 pinsTorex
- What it is
- Voltage supervisor
- Maker
- Torex
- Package
- SOT-23-5
- Pins
- 5
- Details
- CMOS-IC: VDet 4.4V, 5%, Hst, +Rst PPO, -Rst ODO, Wt=6.25ms, Rt=3.13ms
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
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.
Integrated circuit
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.
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.
Printed with a code easy to misread as 40D
One character differs, and it is one that is easy to confuse under a lamp. Each code has a page of its own.
Codes not listed here are printed on 3 more parts.
Did you find your part?
Open this in the search to correct a character or try another package.