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SMD code A1s

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.

The last letter, s, is lower case, which on NXP and Philips parts is a date or factory code, so it was set aside and A1 was searched.

211 parts are printed A1s

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.

  • S-LBAW56DW1T1GSOT-363Switching diode, 6 pins, LRCSwitching diodeSOT-3636 pinsLRC
    What it is
    Switching diode
    Maker
    LRC
    Package
    SOT-363
    Pins
    6
    Details
    Switching diode, VR 70 V, IF 200 mA, VF Max 0.715 V
    Source
    Manufacturer datasheet

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

  • S-LBAW56LT1GSOT-23Switching diode, 3 pins, LRCSwitching diodeSOT-233 pinsLRC
    What it is
    Switching diode
    Maker
    LRC
    Package
    SOT-23
    Pins
    3
    Details
    Switching diode, VR 100 V, IF 200 mA, VF Max 1 V
    Source
    Manufacturer datasheet

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

  • S-LBAW56LT1G-SSOT-23Switching diode, 3 pins, LRCSwitching diodeSOT-233 pinsLRC
    What it is
    Switching diode
    Maker
    LRC
    Package
    SOT-23
    Pins
    3
    Details
    Switching diode, VR 100 V, IF 200 mA, VF Max 1 V
    Source
    Manufacturer datasheet

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

  • S-LBAW56WT1GSOT-323Switching diode, 3 pins, LRCSwitching diodeSOT-3233 pinsLRC
    What it is
    Switching diode
    Maker
    LRC
    Package
    SOT-323
    Pins
    3
    Details
    Switching diode, VR 100 V, IF 200 mA, VF Max 1.25 V
    Source
    Manufacturer datasheet

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

  • S-LBAW56WT1G-SSOT-323Switching diode, 3 pins, LRCSwitching diodeSOT-3233 pinsLRC
    What it is
    Switching diode
    Maker
    LRC
    Package
    SOT-323
    Pins
    3
    Details
    Switching diode, VR 100 V, IF 200 mA, VF Max 1.25 V
    Source
    Manufacturer datasheet

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

  • S-LSI1013N3T5GSOT-883P-channel MOSFET, 3 pins, LRCP-channel MOSFETSOT-8833 pinsLRC
    What it is
    P-channel MOSFET
    Maker
    LRC
    Package
    SOT-883
    Pins
    3
    Details
    MOSFET, P-Channel(with ESD), VDSS 20 V, VGS 6 V
    Source
    Manufacturer datasheet

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

  • S-SOD4001-SHSOD-123FRectifier, 2 pins, LRCRectifierSOD-123F2 pinsLRC
    What it is
    Rectifier
    Maker
    LRC
    Package
    SOD-123F
    Pins
    2
    Details
    Rectifier, VPK 50 V, IO @ TL 1 A, TL@°C 75
    Source
    Manufacturer datasheet

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

  • SBAW56LSOT-23Switching diode, 3 pins, onsemiSwitching diodeSOT-233 pinsonsemi
    What it is
    Switching diode
    Maker
    onsemi
    Package
    SOT-23
    Pins
    3
    Details
    Dual Switching Diode Common Anode
    Source
    Manufacturer datasheet

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

  • SBAW56TSOT-416Switching diode, 3 pins, onsemiSwitching diodeSOT-4163 pinsonsemi
    What it is
    Switching diode
    Maker
    onsemi
    Package
    SOT-416
    Pins
    3
    Details
    Dual Switching Diode
    Source
    Manufacturer datasheet

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

  • SBAW56WSOT-323Switching diode, 3 pins, onsemiSwitching diodeSOT-3233 pinsonsemi
    What it is
    Switching diode
    Maker
    onsemi
    Package
    SOT-323
    Pins
    3
    Details
    Dual Switching Diode, Common Anode
    Source
    Manufacturer datasheet

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

  • SM4001FL-CSOD-123FRectifier, 2 pins, SeCoSRectifierSOD-123F2 pinsSeCoS
    What it is
    Rectifier
    Maker
    SeCoS
    Package
    SOD-123F
    Pins
    2
    Source
    Manufacturer datasheet

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

  • SM4001FLCR-CSOD-123FRectifier, 2 pins, SeCoSRectifierSOD-123F2 pinsSeCoS
    What it is
    Rectifier
    Maker
    SeCoS
    Package
    SOD-123F
    Pins
    2
    Source
    Manufacturer datasheet

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

  • 3 more parts have no package on record

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.

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.

N-channel MOSFET pair

Diode range, part lifted. Test drain to source first, then short gate to source and test again. Test each MOSFET on its own pins, as the datasheet's pinout gives them.

Working, it reads

Red probe on the source, black on the drain: 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. A drain short can be the load. 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.

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