SMD code HM in SOT-323
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.
3 parts in SOT-323 are printed HM
Not sure which one you have?
Answer up to 4 quick questions and these 27 parts are ranked, with a meter test that settles it. It works on a dead part too.
2SC4248SOT-323RF transistor, ToshibaRF transistorToshiba
- What it is
- RF transistor
- Maker
- Toshiba
- Package
- SOT-323
- Pins
- 3
- Details
- Si-npn: UHF-Osc, 20V, 30mA, 100mW, B=70..130, 4GHz
- Source
- Published code list
Is it dead? The meter test is below: Bipolar transistor.
DDZX9693WSOT-323Diodes IncorporatedNot recordedDiodes Incorporated
- What it is
- Not recorded
- Maker
- Diodes Incorporated
- Package
- SOT-323
- Pins
- 3
- Details
- Z-diode: 7,5V±5%, 200mW
- Source
- Published code list
Is it dead? The meter test is below: Silicon diode.
MMBZ5232BWSOT-323Zener diode, JinYu semiconductorZener diodeJinYu semiconductor
- What it is
- Zener diode
- Maker
- JinYu semiconductor
- Package
- SOT-323
- Pins
- 3
- Source
- Published code list
Is it dead? The meter test is below: Zener diode.
12 more parts have no package on record. Nothing rules them out, so they stay.
74HC1G125GWNXPNot recordedNXP
- What it is
- Not recorded
- Maker
- NXP
- Package
- Not recorded
- Pins
- Not recorded
- Details
- CMOS logic IC: Bus buffer gate with 3-state output
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
BD48L54GVoltage supervisor, ROHMVoltage supervisorROHM
- What it is
- Voltage supervisor
- Maker
- ROHM
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Voltage Detector
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
BU46L282GVoltage supervisor, ROHMVoltage supervisorROHM
- What it is
- Voltage supervisor
- Maker
- ROHM
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Voltage detector IC: 2.8V±1%, -Reset PPO, Rdt=200ms
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
BU4820FVoltage supervisor, ROHMVoltage supervisorROHM
- What it is
- Voltage supervisor
- Maker
- ROHM
- Package
- Not recorded
- Pins
- Not recorded
- Details
- CMOS-IC: Voltage Detector 2V, -Reset Open drain output
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
BU4820FWEVoltage supervisor, ROHMVoltage supervisorROHM
- What it is
- Voltage supervisor
- Maker
- ROHM
- Package
- Not recorded
- Pins
- Not recorded
- Details
- CMOS-IC: Voltage Detector 2V, -Reset Open drain output
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
BU4820GVoltage supervisor, ROHMVoltage supervisorROHM
- What it is
- Voltage supervisor
- Maker
- ROHM
- Package
- Not recorded
- Pins
- Not recorded
- Details
- CMOS-IC: Voltage Detector 2V, -Reset Open drain output
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
IXD5127C34BNRVoltage supervisor, IXYSVoltage supervisorIXYS
- What it is
- Voltage supervisor
- Maker
- IXYS
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Voltage detector IC: 3.4V±0.8%, -Reset PPO, -MR, 100ms Rt delay
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
IXD5127N34GNRVoltage supervisor, IXYSVoltage supervisorIXYS
- What it is
- Voltage supervisor
- Maker
- IXYS
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Voltage detector IC: 3.4V±0.8%, +Reset ODO, -MR, 100ms Rt delay
- Source
- Published code list
Is it dead? The meter test is below: Integrated circuit.
LT4ME7.0ATVS diode, Lite-On SemiconductorTVS diodeLite-On Semiconductor
- What it is
- TVS diode
- Maker
- Lite-On Semiconductor
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Transient voltage supressor: Vrwm=7.0V, Vbr=7.78..8.60V, Ipp=33.3A, 400W(1ms)
- Source
- Published code list
Is it dead? The meter test is below: TVS or ESD protection diode.
P2SMSJ7.0ATVS diode, YeashinTVS diodeYeashin
- What it is
- TVS diode
- Maker
- Yeashin
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Transient voltage supressor: Vrwm=7.0V, Vbr=7.78..8.6V, Ipp=16.7A, 200W(1ms)
- Source
- Published code list
Is it dead? The meter test is below: TVS or ESD protection diode.
SMF4L7.0AQTVS diode, Diodes IncorporatedTVS diodeDiodes Incorporated
- What it is
- TVS diode
- Maker
- Diodes Incorporated
- Package
- Not recorded
- Pins
- Not recorded
- Details
- Transient voltage supressor: Vrwm=7V, Vbr=7.78..8.6V, Ipp=33.3A, 400W(1ms)
- Source
- Published code list
Is it dead? The meter test is below: TVS or ESD protection diode.
SN74LVC1G17QDRYTexas InstrumentsNot recordedTexas Instruments
- What it is
- Not recorded
- Maker
- Texas Instruments
- Package
- Not recorded
- Pins
- Not recorded
- Details
- CMOS logic IC: Buffer with Schmitt-trigger input
- 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.
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.
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.
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.
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.
Codes that begin with HM
For a marking with its end worn or burnt off. Each code has a page of its own.
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