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SMD code AU in QFN

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 33 parts are ranked, with a meter test that settles it. It works on a dead part too.

  • RT8805CGQVQFNRichtekNot recordedNot recordedRichtek
    What it is
    Not recorded
    Maker
    Richtek
    Package
    QFN
    Pins
    Not recorded
    Details
    PWM controller
    Source
    Published code list

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

  • RT8805CPQVQFNRichtekNot recordedNot recordedRichtek
    What it is
    Not recorded
    Maker
    Richtek
    Package
    QFN
    Pins
    Not recorded
    Details
    PWM controller
    Source
    Published code list

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

  • 13 more parts have no package on record. Nothing rules them out, so they stay.
    • AOZ1084DIDC-DC converter, Alpha & Omega SemiconductorDC-DC converterNot recordedAlpha & Omega Semiconductor
      What it is
      DC-DC converter
      Maker
      Alpha & Omega Semiconductor
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Synchronous buck regulator
      Source
      Manufacturer datasheet

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

    • BZX884B9V1LZener diode, VishayZener diodeNot recordedVishay
      What it is
      Zener diode
      Maker
      Vishay
      Package
      Not recorded
      Pins
      Not recorded
      Details
      9.1 V Zener diode
      Source
      Manufacturer datasheet

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

    • NCP114AMX360LDO regulator, onsemiLDO regulatorNot recordedonsemi
      What it is
      LDO regulator
      Maker
      onsemi
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Voltage Regulator - CMOS Low Dropout
      Source
      Manufacturer datasheet

      Is it dead? The meter test is below: Voltage regulator.

    • NCP380HMU21AAP-channel MOSFET, onsemiP-channel MOSFETNot recordedonsemi
      What it is
      P-channel MOSFET
      Maker
      onsemi
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Fixed/Adjustable Current-Limiting Power-Distribution Switches
      Source
      Manufacturer datasheet

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

    • NLAS5223CLMUAnalog switch, onsemiAnalog switchNot recordedonsemi
      What it is
      Analog switch
      Maker
      onsemi
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Ultra-Low 0.35  Dual SPDT Analog Switch
      Source
      Manufacturer datasheet

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

    • 7WB3126AMXonsemiNot recordedNot recordedonsemi
      What it is
      Not recorded
      Maker
      onsemi
      Package
      Not recorded
      Pins
      Not recorded
      Details
      CMOS logic IC: 2-Bit bus switch
      Source
      Published code list

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

    • 7WB3126BMXonsemiNot recordedNot recordedonsemi
      What it is
      Not recorded
      Maker
      onsemi
      Package
      Not recorded
      Pins
      Not recorded
      Details
      CMOS logic IC: 2-Bit bus switch
      Source
      Published code list

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

    • 74AUP1G158GFNXPNot recordedNot recordedNXP
      What it is
      Not recorded
      Maker
      NXP
      Package
      Not recorded
      Pins
      Not recorded
      Details
      CMOS logic IC: 2-input inverting multiplexer
      Source
      Published code list

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

    • 74AUP1G158GMNXPNot recordedNot recordedNXP
      What it is
      Not recorded
      Maker
      NXP
      Package
      Not recorded
      Pins
      Not recorded
      Details
      CMOS logic IC: 2-input inverting multiplexer
      Source
      Published code list

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

    • 74AUP1G158GNNXPNot recordedNot recordedNXP
      What it is
      Not recorded
      Maker
      NXP
      Package
      Not recorded
      Pins
      Not recorded
      Details
      CMOS logic IC: 2-input inverting multiplexer
      Source
      Published code list

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

    • 74AUP1G158GSNXPNot recordedNot recordedNXP
      What it is
      Not recorded
      Maker
      NXP
      Package
      Not recorded
      Pins
      Not recorded
      Details
      CMOS logic IC: 2-input inverting multiplexer
      Source
      Published code list

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

    • BFP540FESD4 pins, InfineonNot recorded4 pinsInfineon
      What it is
      Not recorded
      Maker
      Infineon
      Package
      Not recorded
      Pins
      4
      Source
      Published code list

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

    • IXD1504A3517R-GLDO regulator, IXYSLDO regulatorNot recordedIXYS
      What it is
      LDO regulator
      Maker
      IXYS
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Linear voltage regulator IC: LDO, 3.5V±1%, 150mA, +CE
      Source
      Published code list

      Is it dead? The meter test is below: Voltage regulator.

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.

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.

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.

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.

Printed with a code easy to misread as AU

One character differs, and it is one that is easy to confuse under a lamp. Each code has a page of its own.

Codes that begin with AU

For a marking with its end worn or burnt off. Each code has a page of its own.

Codes not listed here are printed on 60 more parts.

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