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SMD code QI- 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.

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.

Nothing is printed exactly QI-

These parts are printed with a character that is easy to misread as what you typed. The odd one out is marked on each.

  • ILC5062IC31Xprinted D1SOT-3233 pins, IMPNot recorded3 pinsIMP

    Printed D1 on the part. Easy to misread as QI-. Check that character with a loupe before you order anything.

    What it is
    Not recorded
    Maker
    IMP
    Package
    SOT-323
    Pins
    3
    Details
    CMOS-IC: Voltage Detector 3.1V±2%, -Reset Push-pull output
    Source
    Published code list

    Is it dead? The meter test is below: Integrated circuit.

  • MCP121T-315E/LBprinted DLSOT-3233 pins, MicrochipNot recorded3 pinsMicrochip

    Printed DL on the part. Easy to misread as QI-. Check that character with a loupe before you order anything.

    What it is
    Not recorded
    Maker
    Microchip
    Package
    SOT-323
    Pins
    3
    Source
    Published code list

    Is it dead? The meter test is below: This part.

  • MMBD2005printed DISOT-3233 pins, MotorolaNot recorded3 pinsMotorola

    Printed DI on the part. Easy to misread as QI-. Check that character with a loupe before you order anything.

    What it is
    Not recorded
    Maker
    Motorola
    Package
    SOT-323
    Pins
    3
    Details
    Si-diode: Dual, Sw, 30V, 200mA, 150mW, Vf<0,95V(10mA), <2pF
    Source
    Published code list

    Is it dead? The meter test is below: Silicon diode.

  • MMBD2005T1printed DISOT-3233 pins, onsemiNot recorded3 pinsonsemi

    Printed DI on the part. Easy to misread as QI-. Check that character with a loupe before you order anything.

    What it is
    Not recorded
    Maker
    onsemi
    Package
    SOT-323
    Pins
    3
    Source
    Published code list

    Is it dead? The meter test is below: This part.

  • STP7401S32RGprinted 01SOT-323P-channel MOSFET, 3 pins, StansonP-channel MOSFET3 pinsStanson

    Printed 01 on the part. Easy to misread as QI-. Check that character with a loupe before you order anything.

    What it is
    P-channel MOSFET
    Maker
    Stanson
    Package
    SOT-323
    Pins
    3
    Source
    Published code list

    Is it dead? The meter test is below: P-channel MOSFET.

  • 10 more parts have no package on record. Nothing rules them out, so they stay.
    • 1N4148LW-Cprinted D1Switching diode, SeCoSSwitching diodeNot recordedSeCoS

      Printed D1 on the part. Easy to misread as QI-. Check that character with a loupe before you order anything.

      What it is
      Switching diode
      Maker
      SeCoS
      Package
      Not recorded
      Pins
      Not recorded
      Source
      Manufacturer datasheet

      Is it dead? The meter test is below: Silicon diode.

    • BFU610Fprinted D1RF transistor, 4 pins, NXPRF transistor4 pinsNXP

      Printed D1 on the part. Easy to misread as QI-. Check that character with a loupe before you order anything.

      What it is
      RF transistor
      Maker
      NXP
      Package
      Not recorded
      Pins
      4
      Details
      NPN wideband silicon RF transistor
      Source
      Manufacturer datasheet

      Is it dead? The meter test is below: Bipolar transistor.

    • BGU6005/N2printed D1RF amplifier (MMIC), 6 pins, NXPRF amplifier (MMIC)6 pinsNXP

      Printed D1 on the part. Easy to misread as QI-. Check that character with a loupe before you order anything.

      What it is
      RF amplifier (MMIC)
      Maker
      NXP
      Package
      Not recorded
      Pins
      6
      Details
      Low Noise Amplifier MMIC for GPS, GLONASS, Galileo and Compass
      Source
      Manufacturer datasheet

      Is it dead? The meter test is below: RF amplifier.

    • DS520-40A1printed D1Schottky diode, JSCJSchottky diodeNot recordedJSCJ

      Printed D1 on the part. Easy to misread as QI-. Check that character with a loupe before you order anything.

      What it is
      Schottky diode
      Maker
      JSCJ
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Schottky diode, 40 V, 0.2 A
      Source
      Manufacturer datasheet

      Is it dead? The meter test is below: Schottky diode.

    • ESDALC6V1-1BU2printed D1TVS diode, STMicroelectronicsTVS diodeNot recordedSTMicroelectronics

      Printed D1 on the part. Easy to misread as QI-. Check that character with a loupe before you order anything.

      What it is
      TVS diode
      Maker
      STMicroelectronics
      Package
      Not recorded
      Pins
      Not recorded
      Source
      Manufacturer datasheet

      Is it dead? The meter test is below: TVS or ESD protection diode.

    • GSRB520B40printed D1Schottky diode, Good-ArkSchottky diodeNot recordedGood-Ark

      Printed D1 on the part. Easy to misread as QI-. Check that character with a loupe before you order anything.

      What it is
      Schottky diode
      Maker
      Good-Ark
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Schottky diode, 40 V, 200 mA
      Source
      Manufacturer datasheet

      Is it dead? The meter test is below: Schottky diode.

    • LDTA114GET1Gprinted Q1Digital transistor (PNP, resistors built in), LRCDigital transistor (PNP, resistors built in)Not recordedLRC

      Printed Q1 on the part. Easy to misread as QI-. Check that character with a loupe before you order anything.

      What it is
      Digital transistor (PNP, resistors built in)
      Maker
      LRC
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Digital transistor (bias resistors built in), PNP, IC 100 mA, VCEO 50 V
      Source
      Manufacturer datasheet

      Is it dead? The meter test is below: Digital transistor.

    • LP2301LT1Gprinted 01P-channel MOSFET, LRCP-channel MOSFETNot recordedLRC

      Printed 01 on the part. Easy to misread as QI-. Check that character with a loupe before you order anything.

      What it is
      P-channel MOSFET
      Maker
      LRC
      Package
      Not recorded
      Pins
      Not recorded
      Details
      MOSFET, P-Channel, VDSS 20 V, VGS 8 V
      Source
      Manufacturer datasheet

      Is it dead? The meter test is below: P-channel MOSFET.

    • MAR-1+printed 01RF amplifier (MMIC), Mini-CircuitsRF amplifier (MMIC)Not recordedMini-Circuits

      Printed 01 on the part. Easy to misread as QI-. Check that character with a loupe before you order anything.

      What it is
      RF amplifier (MMIC)
      Maker
      Mini-Circuits
      Package
      Not recorded
      Pins
      Not recorded
      Details
      MMIC amplifier, DC-1 GHz
      Source
      Manufacturer datasheet

      Is it dead? The meter test is below: RF amplifier.

    • MAR-1SM+printed 01RF amplifier (MMIC), Mini-CircuitsRF amplifier (MMIC)Not recordedMini-Circuits

      Printed 01 on the part. Easy to misread as QI-. Check that character with a loupe before you order anything.

      What it is
      RF amplifier (MMIC)
      Maker
      Mini-Circuits
      Package
      Not recorded
      Pins
      Not recorded
      Details
      MMIC amplifier, DC-1 GHz
      Source
      Manufacturer datasheet

      Is it dead? The meter test is below: RF amplifier.

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.

This part

Diode range and ohms range, part lifted.

Working, it reads

Depends on what it is. The datasheet, or an identical part, says.

Dead, it reads

  • Between two pins, the same reading both ways, near 0 V with a continuous beep: shorted.
  • Open between every pair of pins: failed open, or a part that reads open when working.
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.

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.

P-channel MOSFET

Diode range, part lifted. Test drain to source first, then short gate to source and test again.

Working, it reads

Red probe on the drain, black on the source: about 0.4 to 0.9 V, the body diode. Open the other way. The gate reads open to both other pins, both ways.

Dead, it reads

  • Drain to source the same both ways, near 0 V with a continuous beep, and still so after shorting gate to source: shorted. The classic failure.
  • The gate reads low to source or drain: gate shorted. Often all three pins end up shorted together.
  • No body diode at all: failed open.
On the board
the gate usually has a resistor to the source, so gate to source reads that resistor, which is not a fault. Lift a leg to be sure.
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 diode range can charge the gate enough to turn the part on, and then drain to source reads near 0 both ways on a good part. Short gate to source and test again before you condemn it.

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.

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.

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.

Digital transistor

Ohms range, part lifted. The datasheet gives the built-in resistors: R1 in series with the base, R2 from base to emitter.

Working, it reads

Base to emitter reads about R1 plus R2 either way round, about 20 kΩ on a 10 k and 10 k part, give or take their wide tolerance. Collector to emitter reads open. A part with no R2 reads a junction behind R1 one way instead.

Dead, it reads

  • Collector to emitter the same both ways, near 0 Ω with a continuous beep: shorted.
  • From the base, open or far above R1 plus R2: R1 has failed. Static damage shows here most often.
  • Base to emitter near 0 Ω: failed short.
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:
The readings depend on the resistor values, so an identical part elsewhere on the board is the surest reference. Measure it the same way.
Watch for:
On the diode range a good part with 10 kΩ resistors reads open on every pair, so a good part looks dead there. Use the ohms range.

A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

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