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SMD code D1-

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.

189 parts are printed D1-

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.

  • BZX384B51-Q1SOD-323Zener diode, 2 pins, Formosa MicrosemiZener diodeSOD-3232 pinsFormosa Microsemi
    What it is
    Zener diode
    Maker
    Formosa Microsemi
    Package
    SOD-323
    Pins
    2
    Source
    Manufacturer datasheet

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

  • CHN1GPSOT-23-5Switching diode, 5 pins, ChenmkoSwitching diodeSOT-23-55 pinsChenmko
    What it is
    Switching diode
    Maker
    Chenmko
    Package
    SOT-23-5
    Pins
    5
    Details
    SWITCHING DIODE, 80 V, 25 mA
    Source
    Manufacturer datasheet

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

  • CMS01P06Y-HFSOT-223P-channel MOSFET, 4 pins, ComchipP-channel MOSFETSOT-2234 pinsComchip
    What it is
    P-channel MOSFET
    Maker
    Comchip
    Package
    SOT-223
    Pins
    4
    Details
    -60 V, -1.9 A P-channel MOSFET
    Source
    Manufacturer datasheet

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

  • LMSZ5226BT1GSOD-123Zener diode, 2 pins, LRCZener diodeSOD-1232 pinsLRC
    What it is
    Zener diode
    Maker
    LRC
    Package
    SOD-123
    Pins
    2
    Details
    Zener diode, VZ Min 3.14 V, VZ Nom 3.3 V, VZ Max 3.47 V
    Source
    Manufacturer datasheet

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

  • LRB520BS-40T5GSOD-882Schottky diode, 2 pins, LRCSchottky diodeSOD-8822 pinsLRC
    What it is
    Schottky diode
    Maker
    LRC
    Package
    SOD-882
    Pins
    2
    Details
    Schottky diode, VR 40 V, IF 0.2 A, VF Max 0.39 V
    Source
    Manufacturer datasheet

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

  • MM3Z2V7BWSOD-323Zener diode, 2 pins, YFWZener diodeSOD-3232 pinsYFW
    What it is
    Zener diode
    Maker
    YFW
    Package
    SOD-323
    Pins
    2
    Source
    Manufacturer datasheet

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

  • MMBZ5226BSOT-23Zener diode, 3 pins, DC ComponentsZener diodeSOT-233 pinsDC Components
    What it is
    Zener diode
    Maker
    DC Components
    Package
    SOT-23
    Pins
    3
    Source
    Manufacturer datasheet

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

  • MMBZ5226BTWSOT-363Zener diode, 6 pins, PanjitZener diodeSOT-3636 pinsPanjit
    What it is
    Zener diode
    Maker
    Panjit
    Package
    SOT-363
    Pins
    6
    Source
    Manufacturer datasheet

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

  • MMBZ5226BWSOT-323Zener diode, 3 pins, DC ComponentsZener diodeSOT-3233 pinsDC Components
    What it is
    Zener diode
    Maker
    DC Components
    Package
    SOT-323
    Pins
    3
    Source
    Manufacturer datasheet

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

  • MMSZ5226ASOD-123Zener diode, 2 pins, Galaxy MicroelectronicsZener diodeSOD-1232 pinsGalaxy Microelectronics
    What it is
    Zener diode
    Maker
    Galaxy Microelectronics
    Package
    SOD-123
    Pins
    2
    Details
    3.3V, 500mW, Surface Mount Zener Diodes
    Source
    Manufacturer datasheet

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

  • 5 more parts have no package on record
    • DS520-40A1Schottky diode, JSCJSchottky diodeNot recordedNot recordedJSCJ
      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.

    • ESDALC6V1-1BU2TVS diode, STMicroelectronicsTVS diodeNot recordedNot recordedSTMicroelectronics
      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.

    • GSRB520B40Schottky diode, Good-ArkSchottky diodeNot recordedNot recordedGood-Ark
      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.

    • MMBZ5226BWSZener diode, Taitron ComponentsZener diodeNot recordedNot recordedTaitron Components
      What it is
      Zener diode
      Maker
      Taitron Components
      Package
      Not recorded
      Pins
      Not recorded
      Details
      SMD Zener Diodes (Three Terminals) - 200mW
      Source
      Manufacturer datasheet

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

    • MMSZ5226AHEZener diode, Galaxy MicroelectronicsZener diodeNot recordedNot recordedGalaxy Microelectronics
      What it is
      Zener diode
      Maker
      Galaxy Microelectronics
      Package
      Not recorded
      Pins
      Not recorded
      Details
      3.3V, 500mW, Surface Mount Zener Diodes
      Source
      Manufacturer datasheet

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

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.

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.

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.

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.

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