SMD code 3V9
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.
18 parts are printed 3V9
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.
MFPZ3V9SOD-123FZener diode, 2 pins, Taitron ComponentsZener diodeSOD-123F2 pinsTaitron Components
- What it is
- Zener diode
- Maker
- Taitron Components
- Package
- SOD-123F
- Pins
- 2
- Details
- SMD Zener Diodes (Two Terminals) - 800mW
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
MM3Z3V9CW-P2-HFSOD-323Zener diode, 2 pins, ComchipZener diodeSOD-3232 pinsComchip
- What it is
- Zener diode
- Maker
- Comchip
- Package
- SOD-323
- Pins
- 2
- Details
- 3.9 V 200 mW zener diode
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
TAR5S39SOT-23-5LDO regulator, 5 pins, ToshibaLDO regulatorSOT-23-55 pinsToshiba
- What it is
- LDO regulator
- Maker
- Toshiba
- Package
- SOT-23-5
- Pins
- 5
- Details
- TAR5S15 to TAR5S50 Point Regulators (Low-Dropout Regulator)
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Voltage regulator.
BZD27C3V9PSOD-123FZener diode, 2 pins, PanjitZener diodeSOD-123F2 pinsPanjit
- What it is
- Zener diode
- Maker
- Panjit
- Package
- SOD-123F
- Pins
- 2
- Details
- 3.9 V Zener diode
- Source
- Published code list
Is it dead? The meter test is below: Zener diode.
CHPZ3V9PTSOT-23Zener diode, 3 pins, Chenmko EnterpriseZener diodeSOT-233 pinsChenmko Enterprise
- What it is
- Zener diode
- Maker
- Chenmko Enterprise
- Package
- SOT-23
- Pins
- 3
- Details
- Zener diode: Dual, 3.7..4.1V, Izt=5mA, Zzt=90, 350mW
- Source
- Published code list
Is it dead? The meter test is below: Zener diode.
MZ0.5GN3V9SOD-80Zener diode, 2 pins, Master Instrument Corporation of ShanghaiZener diodeSOD-802 pinsMaster Instrument Corporation of Shanghai
- What it is
- Zener diode
- Maker
- Master Instrument Corporation of Shanghai
- Package
- SOD-80
- Pins
- 2
- Details
- Zener diode: 3.9V+-5%, Zzt=90, Izt=95mA, 500mW
- Source
- Published code list
Is it dead? The meter test is below: Zener diode.
PZM3.9NBSOT-233 pins, NXPNot recordedSOT-233 pinsNXP
- What it is
- Not recorded
- Maker
- NXP
- Package
- SOT-23
- Pins
- 3
- Details
- 3.9V 300mW Zener
- Source
- Published code list
Is it dead? The meter test is below: Zener diode.
TAR5S39USOT-3535 pins, ToshibaNot recordedSOT-3535 pinsToshiba
- What it is
- Not recorded
- Maker
- Toshiba
- Package
- SOT-353
- Pins
- 5
- Details
- VR-IC: LDO, CE, 3,9V±1%, 200mA
- Source
- Published code list
Is it dead? The meter test is below: Voltage regulator.
TAR5SB39SOT-23-55 pins, ToshibaNot recordedSOT-23-55 pinsToshiba
- What it is
- Not recorded
- Maker
- Toshiba
- Package
- SOT-23-5
- Pins
- 5
- Details
- LDO reg 3.9V 0.2A
- Source
- Published code list
Is it dead? The meter test is below: Voltage regulator.
6 more parts have no package on record
BZY55-C3V9Zener diode, Taiwan SemiconductorZener diodeNot recordedNot recordedTaiwan Semiconductor
- What it is
- Zener diode
- Maker
- Taiwan Semiconductor
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Zener diode: 3.71..4.10V, Izt=5mA, Zzt=85, 500mW
- Source
- Published code list
Is it dead? The meter test is below: Zener diode.
CDZ55C3V9Zener diode, Crownpo TechnologyZener diodeNot recordedNot recordedCrownpo Technology
- What it is
- Zener diode
- Maker
- Crownpo Technology
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Zener diode: 3.71..4.10V, Zzt=85, Izt=5mA, 500mW
- Source
- Published code list
Is it dead? The meter test is below: Zener diode.
CDZ55C3V9SZener diode, Crownpo TechnologyZener diodeNot recordedNot recordedCrownpo Technology
- What it is
- Zener diode
- Maker
- Crownpo Technology
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Zener diode: 3.71..4.10V, Zzt=85, Izt=5mA, 500mW
- Source
- Published code list
Is it dead? The meter test is below: Zener diode.
CTZ55C3V9Zener diode, Compact TechnologyZener diodeNot recordedNot recordedCompact Technology
- What it is
- Zener diode
- Maker
- Compact Technology
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Zener diode: 3.71..4.10V, Izt=5mA, Zzt=85, 500mW
- Source
- Published code list
Is it dead? The meter test is below: Zener diode.
CZRNC55C3V9-GZener diode, ComchipZener diodeNot recordedNot recordedComchip
- What it is
- Zener diode
- Maker
- Comchip
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Zener diode: 3.71..4.10V, Zt=85, Izt=5mA, 500mW
- Source
- Published code list
Is it dead? The meter test is below: Zener diode.
CZRSC55C3V9-GZener diode, ComchipZener diodeNot recordedNot recordedComchip
- What it is
- Zener diode
- Maker
- Comchip
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Zener diode: 3.71..4.10V, Zt=85, Izt=5mA, 500mW
- Source
- Published code list
Is it dead? The meter test is below: Zener 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.
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.
Voltage regulator
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.
Codes that begin with 3V9
For a marking with its end worn or burnt off. Each code has a page of its own.
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