SMD code HJ 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.
5 parts in SOT-23 are printed HJ
Not sure which one you have?
Answer up to 4 quick questions and these 14 parts are ranked, with a meter test that settles it. It works on a dead part too.
AP130-43RSOT-23AnachipNot recordedAnachip
- What it is
- Not recorded
- Maker
- Anachip
- Package
- SOT-23
- Pins
- 3
- Details
- VR-IC: LDO, 4,3V±2%, 300mA
- Source
- Published code list
Is it dead? The meter test is below: Voltage regulator.
DDZX9690SOT-23Zener diode, Diodes IncorporatedZener diodeDiodes Incorporated
- What it is
- Zener diode
- Maker
- Diodes Incorporated
- Package
- SOT-23
- Pins
- 3
- Details
- Z-diode: 5,6V±5%, 500mW
- Source
- Published code list
Is it dead? The meter test is below: Zener diode.
ELM7648LDBSOT-23Voltage supervisor, ELM TechnologyVoltage supervisorELM Technology
- What it is
- Voltage supervisor
- Maker
- ELM Technology
- Package
- SOT-23
- Pins
- 3
- Details
- Voltage detector IC: 4.8V±2%, -Reset PPO, Rdt=50ms
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
RT9818B-42PVSOT-23Voltage supervisor, RichtekVoltage supervisorRichtek
- What it is
- Voltage supervisor
- Maker
- Richtek
- Package
- SOT-23
- Pins
- 3
- Details
- Voltage Detector
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
RT9819C-27PVSOT-23Voltage supervisor, RichtekVoltage supervisorRichtek
- What it is
- Voltage supervisor
- Maker
- Richtek
- Package
- SOT-23
- Pins
- 3
- Details
- Voltage Detector
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
9 more parts have no package on record. Nothing rules them out, so they stay.
MM5Z8V2BZener diode, Formosa MicrosemiZener diodeFormosa Microsemi
- What it is
- Zener diode
- Maker
- Formosa Microsemi
- Package
- Not recorded
- Pins
- Not recorded
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
MM5Z8V2B-Q1Zener diode, Formosa MicrosemiZener diodeFormosa Microsemi
- What it is
- Zener diode
- Maker
- Formosa Microsemi
- Package
- Not recorded
- Pins
- Not recorded
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
NCP177BMX330LDO regulator, onsemiLDO regulatoronsemi
- What it is
- LDO regulator
- Maker
- onsemi
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Linear Voltage Regulator - Fast Transient Response, Enable
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Voltage regulator.
NCP186BMX350LDO regulator, onsemiLDO regulatoronsemi
- What it is
- LDO regulator
- Maker
- onsemi
- Package
- Not recorded
- Pins
- Not recorded
- Details
- LDO Regulator - Fast Transient Response Low Voltage
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Voltage regulator.
2SC3828RF transistor, ToshibaRF transistorToshiba
- What it is
- RF transistor
- Maker
- Toshiba
- Package
- Not recorded
- Pins
- Not recorded
- Details
- NPN transistor: TV-UHF-Tuner, 20V, 20mA, 150mW, 1,1GHz, B=40..100
- Source
- Published code list
Is it dead? The meter test is below: Bipolar transistor.
BU4817FVoltage supervisor, ROHMVoltage supervisorROHM
- What it is
- Voltage supervisor
- Maker
- ROHM
- Package
- Not recorded
- Pins
- Not recorded
- Details
- CMOS-IC: Voltage Detector 1,7V, -Reset Open drain output
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
BU4817FWEVoltage supervisor, ROHMVoltage supervisorROHM
- What it is
- Voltage supervisor
- Maker
- ROHM
- Package
- Not recorded
- Pins
- Not recorded
- Details
- CMOS-IC: Voltage Detector 1,7V, -Reset Open drain output
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
BU4817GVoltage supervisor, ROHMVoltage supervisorROHM
- What it is
- Voltage supervisor
- Maker
- ROHM
- Package
- Not recorded
- Pins
- Not recorded
- Details
- CMOS-IC: Voltage Detector 1,7V, -Reset Open drain output
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
KRA559FKECNot recordedKEC
- What it is
- Not recorded
- Maker
- KEC
- Package
- Not recorded
- Pins
- Not recorded
- Details
- PNP transistor: Dual, Sw, 20V, 50mA, 50mW, R1/R2=47k/22k
- Source
- Published code list
Is it dead? The meter test is below: Bipolar 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.
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.
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.
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.
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.
Codes that begin with HJ
For a marking with its end worn or burnt off. Each code has a page of its own.
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