SMD code B7a
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, a, is lower case, which on NXP and Philips parts is a date or factory code, so it was set aside and B7 was searched.
171 parts are printed B7a
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.
BAT54AWSOT-323Schottky diode, 3 pins, UMWSchottky diodeSOT-3233 pinsUMW
- What it is
- Schottky diode
- Maker
- UMW
- Package
- SOT-323
- Pins
- 3
- Details
- 30 V surface-mount Schottky barrier diode, dual common anode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
BAV756DWSOT-363Switching diode, 6 pins, DiotecSwitching diodeSOT-3636 pinsDiotec
- What it is
- Switching diode
- Maker
- Diotec
- Package
- SOT-363
- Pins
- 6
- Details
- SMD Small Signal Diode Arrays
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
BZT52H-C3V6SOD-123FZener diode, 2 pins, NexperiaZener diodeSOD-123F2 pinsNexperia
- What it is
- Zener diode
- Maker
- Nexperia
- Package
- SOD-123F
- Pins
- 2
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
BZX84-C51SOT-23Zener diode, 3 pins, NexperiaZener diodeSOT-233 pinsNexperia
- What it is
- Zener diode
- Maker
- Nexperia
- Package
- SOT-23
- Pins
- 3
- Pinout
- 1 anode
- 2 not connected
- 3 cathode
- Details
- 51 V approx. ±5% voltage regulator (Zener) diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
CDBF0240-HFSOD-323Schottky diode, 2 pins, ComchipSchottky diodeSOD-3232 pinsComchip
- What it is
- Schottky diode
- Maker
- Comchip
- Package
- SOD-323
- Pins
- 2
- Details
- 45 V, 0.2 A Schottky barrier diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
CDBV3-54A-HFSOT-323Schottky diode, 3 pins, ComchipSchottky diodeSOT-3233 pinsComchip
- What it is
- Schottky diode
- Maker
- Comchip
- Package
- SOT-323
- Pins
- 3
- Details
- 30 V, 0.2 A Schottky barrier diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
GSD2004WSOD-123Switching diode, 2 pins, VishaySwitching diodeSOD-1232 pinsVishay
- What it is
- Switching diode
- Maker
- Vishay
- Package
- SOD-123
- Pins
- 2
- Details
- Small Signal Switching Diode, High Voltage
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
GSD2004W-GSOD-123Switching diode, 2 pins, VishaySwitching diodeSOD-1232 pinsVishay
- What it is
- Switching diode
- Maker
- Vishay
- Package
- SOD-123
- Pins
- 2
- Details
- Small Signal Switching Diode, High Voltage
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Silicon diode.
LBAT54AWT1GSOT-323Schottky diode, 3 pins, LRCSchottky diodeSOT-3233 pinsLRC
- What it is
- Schottky diode
- Maker
- LRC
- Package
- SOT-323
- Pins
- 3
- Details
- Schottky diode, VR 30 V, IF 0.2 A, VF Max 0.4 V
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
6 more parts have no package on record
ACDBUC0240-HFSchottky diode, ComchipSchottky diodeNot recordedNot recordedComchip
- What it is
- Schottky diode
- Maker
- Comchip
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 45 V, 0.2 A Schottky barrier diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
BFU725F/N1RF transistor, 4 pins, NXPRF transistorNot recorded4 pinsNXP
- What it is
- RF transistor
- Maker
- NXP
- Package
- Not recorded
- Pins
- 4
- Details
- NPN wideband silicon germanium RF transistor
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Bipolar transistor.
BGU7008RF amplifier (MMIC), 6 pins, NXPRF amplifier (MMIC)Not recorded6 pinsNXP
- What it is
- RF amplifier (MMIC)
- Maker
- NXP
- Package
- Not recorded
- Pins
- 6
- Details
- SiGe:C Low Noise Amplifier MMIC for GPS, GLONASS, Galileo and Compass
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: RF amplifier.
CDBU0240-HFSchottky diode, ComchipSchottky diodeNot recordedNot recordedComchip
- What it is
- Schottky diode
- Maker
- Comchip
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 45 V, 0.2 A Schottky barrier diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
CDBUR0240-HFSchottky diode, ComchipSchottky diodeNot recordedNot recordedComchip
- What it is
- Schottky diode
- Maker
- Comchip
- Package
- Not recorded
- Pins
- Not recorded
- Details
- 45 V, 0.2 A Schottky barrier diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Schottky diode.
GSEZ12U1000ESD protection diode, Good-ArkESD protection diodeNot recordedNot recordedGood-Ark
- What it is
- ESD protection diode
- Maker
- Good-Ark
- Package
- Not recorded
- Pins
- Not recorded
- Details
- ESD protection diode, VRWM 12 V
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
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.
Schottky diode
Diode range, part lifted or one leg off the pad. Red probe on the anode.
Working, it reads
About 0.15 to 0.45 V anode to cathode, roughly half a silicon diode, and open the other way.
Dead, it reads
- The same reading both ways round, near 0 V with a continuous beep or the same middling value: shorted.
- A reading the wrong way round as well: leaky.
- Open both ways: failed open.
- 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 large Schottky can read about 0.1 V forward and beep like a short, and leaks a little the wrong way when good, more when warm. It is shorted only if it reads the same both ways. Measure it cold, beside an identical cold one.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
Silicon diode
Diode range, part lifted or one leg off the pad. Red probe on the anode.
Working, it reads
About 0.5 to 0.8 V anode to cathode, and open the other way. Small switching diodes read about 0.6 to 0.7 V; large rectifiers can read a little lower.
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: failed open.
- A reading the wrong way round as well: 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 three-pin body can hold two diodes. With a common pin they read two junctions from that pin, just like a transistor; in series they read two drops end to end. Test each pair the datasheet names.
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.
RF amplifier
Voltage, board powered, on the output pin that the bias resistor or choke feeds.
Working, it reads
The output pin sits at the device voltage the datasheet gives, a few volts, below the supply.
Dead, it reads
- Output pin at 0 V, or near 0 Ω to ground with the power off: shorted inside.
- Output pin at the full supply voltage: open inside, no current flowing.
- On the board:
- Measured on the board with power on; the bias network is part of the reading.
- 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 figures depend on the part and its bias resistor. 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.
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.
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 B7a
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 7 more parts.
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