Skip to content

SMD code 1Ds

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 1D was searched.

118 parts are printed 1Ds

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.

  • FMBTA42SOT-23NPN transistor, 3 pins, Formosa MicrosemiNPN transistorSOT-233 pinsFormosa Microsemi
    What it is
    NPN transistor
    Maker
    Formosa Microsemi
    Package
    SOT-23
    Pins
    3
    Source
    Manufacturer datasheet

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

  • FMBTA42-Q1SOT-23NPN transistor, 3 pins, Formosa MicrosemiNPN transistorSOT-233 pinsFormosa Microsemi
    What it is
    NPN transistor
    Maker
    Formosa Microsemi
    Package
    SOT-23
    Pins
    3
    Source
    Manufacturer datasheet

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

  • FMBTA42WSOT-323NPN transistor, 3 pins, Formosa MicrosemiNPN transistorSOT-3233 pinsFormosa Microsemi
    What it is
    NPN transistor
    Maker
    Formosa Microsemi
    Package
    SOT-323
    Pins
    3
    Source
    Manufacturer datasheet

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

  • FMBTA42W-Q1SOT-323NPN transistor, 3 pins, Formosa MicrosemiNPN transistorSOT-3233 pinsFormosa Microsemi
    What it is
    NPN transistor
    Maker
    Formosa Microsemi
    Package
    SOT-323
    Pins
    3
    Source
    Manufacturer datasheet

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

  • HMM3Z2V7T1GSOD-323Zener diode, 2 pins, HXYZener diodeSOD-3232 pinsHXY
    What it is
    Zener diode
    Maker
    HXY
    Package
    SOD-323
    Pins
    2
    Details
    Zener diode, 15 V
    Source
    Manufacturer datasheet

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

  • L2SC4083PWT1GSOT-323NPN transistor, 3 pins, LRCNPN transistorSOT-3233 pinsLRC
    What it is
    NPN transistor
    Maker
    LRC
    Package
    SOT-323
    Pins
    3
    Details
    Bipolar transistor, NPN, IC 50 mA, VCEO 11 V
    Source
    Manufacturer datasheet

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

  • LBTN05300Z4TZHGSOT-223NPN transistor, 4 pins, LRCNPN transistorSOT-2234 pinsLRC
    What it is
    NPN transistor
    Maker
    LRC
    Package
    SOT-223
    Pins
    4
    Details
    Bipolar transistor, NPN, IC 500 mA, VCEO 300 V
    Source
    Manufacturer datasheet

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

  • LM3Z56VPT1GSOD-323Zener diode, 2 pins, LRCZener diodeSOD-3232 pinsLRC
    What it is
    Zener diode
    Maker
    LRC
    Package
    SOD-323
    Pins
    2
    Details
    Zener diode, VZ Min 52 V, VZ Nom 56 V, VZ Max 60 V
    Source
    Manufacturer datasheet

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

  • LM3Z56VT1GSOD-323Zener diode, 2 pins, LRCZener diodeSOD-3232 pinsLRC
    What it is
    Zener diode
    Maker
    LRC
    Package
    SOD-323
    Pins
    2
    Details
    Zener diode, VZ Min 52 V, VZ Nom 56 V, VZ Max 60 V
    Source
    Manufacturer datasheet

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

  • LM5Z56VPT1GSOD-523Zener diode, 2 pins, LRCZener diodeSOD-5232 pinsLRC
    What it is
    Zener diode
    Maker
    LRC
    Package
    SOD-523
    Pins
    2
    Details
    Zener diode, VZ Min 52 V, VZ Nom 56 V, VZ Max 60 V
    Source
    Manufacturer datasheet

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

  • LM5Z56VT1GSOD-523Zener diode, 2 pins, LRCZener diodeSOD-5232 pinsLRC
    What it is
    Zener diode
    Maker
    LRC
    Package
    SOD-523
    Pins
    2
    Details
    Zener diode, VZ Min 52 V, VZ Nom 56 V, VZ Max 60 V
    Source
    Manufacturer datasheet

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

  • LMBTA42LT1GSOT-23NPN transistor, 3 pins, LRCNPN transistorSOT-233 pinsLRC
    What it is
    NPN transistor
    Maker
    LRC
    Package
    SOT-23
    Pins
    3
    Details
    Bipolar transistor, NPN, IC 50 mA, VCEO 300 V
    Source
    Manufacturer datasheet

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

  • MM3Z2V7SOD-323Zener diode, 2 pins, DiotecZener diodeSOD-3232 pinsDiotec
    What it is
    Zener diode
    Maker
    Diotec
    Package
    SOD-323
    Pins
    2
    Details
    SMD Planar Zener Diodes
    Source
    Manufacturer datasheet

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

  • MM3Z2V7BWSOD-323Zener diode, 2 pins, JSMSEMIZener diodeSOD-3232 pinsJSMSEMI
    What it is
    Zener diode
    Maker
    JSMSEMI
    Package
    SOD-323
    Pins
    2
    Source
    Manufacturer datasheet

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

  • 1 more part has no package on record
    • EMB32N03VATN-channel MOSFET, Excelliance MOSN-channel MOSFETNot recordedNot recordedExcelliance MOS
      What it is
      N-channel MOSFET
      Maker
      Excelliance MOS
      Package
      Not recorded
      Pins
      Not recorded
      Details
      30 V, 5.5 A N-channel MOSFET
      Source
      Manufacturer datasheet

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

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.

N-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 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.

NPN transistor

Diode range, part lifted or its base leg off the pad.

Working, it reads

Red probe on the base 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.

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.

Did you find your part?

Open this in the search to correct a character or try another package.