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SMD code Y9y

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, y, is lower case, which on NXP and Philips parts is a date or factory code, so it was set aside and Y9 was searched.

87 parts are printed Y9y

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.

  • ACZRH584C24-HFSOD-523Zener diode, 2 pins, ComchipZener diodeSOD-5232 pinsComchip
    What it is
    Zener diode
    Maker
    Comchip
    Package
    SOD-523
    Pins
    2
    Details
    24 V 0.2 mW zener diode
    Source
    Manufacturer datasheet

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

  • AP2625GYSOT-23-6Dual P-channel MOSFET, 6 pins, Advanced Power ElectronicsDual P-channel MOSFETSOT-23-66 pinsAdvanced Power Electronics
    What it is
    Dual P-channel MOSFET
    Maker
    Advanced Power Electronics
    Package
    SOT-23-6
    Pins
    6
    Details
    30 V, 2 A dual P-channel MOSFET
    Source
    Manufacturer datasheet

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

  • BAT43WSSOD-323Schottky diode, 2 pins, Formosa MicrosemiSchottky diodeSOD-3232 pinsFormosa Microsemi
    What it is
    Schottky diode
    Maker
    Formosa Microsemi
    Package
    SOD-323
    Pins
    2
    Source
    Manufacturer datasheet

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

  • BAT43WS-Q1SOD-323Schottky diode, 2 pins, Formosa MicrosemiSchottky diodeSOD-3232 pinsFormosa Microsemi
    What it is
    Schottky diode
    Maker
    Formosa Microsemi
    Package
    SOD-323
    Pins
    2
    Source
    Manufacturer datasheet

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

  • BZT52C5V1SOD-123Zener diode, 2 pins, VishayZener diodeSOD-1232 pinsVishay
    What it is
    Zener diode
    Maker
    Vishay
    Package
    SOD-123
    Pins
    2
    Source
    Manufacturer datasheet

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

  • BZT52C5V1-GSOD-123Zener diode, 2 pins, VishayZener diodeSOD-1232 pinsVishay
    What it is
    Zener diode
    Maker
    Vishay
    Package
    SOD-123
    Pins
    2
    Details
    525.1 V Zener diode
    Source
    Manufacturer datasheet

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

  • BZX7B18SOD-723Zener diode, 2 pins, Good-ArkZener diodeSOD-7232 pinsGood-Ark
    What it is
    Zener diode
    Maker
    Good-Ark
    Package
    SOD-723
    Pins
    2
    Details
    Zener diode, VZ 18 V, 0.1 W
    Source
    Manufacturer datasheet

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

  • BZX84-C24SOT-23Zener diode, 3 pins, NexperiaZener diodeSOT-233 pinsNexperia
    What it is
    Zener diode
    Maker
    Nexperia
    Package
    SOT-23
    Pins
    3
    Pinout
    • 1 anode
    • 2 not connected
    • 3 cathode
    Details
    24 V approx. ±5% voltage regulator (Zener) diode
    Source
    Manufacturer datasheet

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

  • BZX84-C36,215SOT-23Zener diode, 3 pins, HXYZener diodeSOT-233 pinsHXY
    What it is
    Zener diode
    Maker
    HXY
    Package
    SOT-23
    Pins
    3
    Details
    Zener diode, 75 V, 0.05 A
    Source
    Manufacturer datasheet

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

  • BZX84B24-CSOT-23Zener diode, 3 pins, SeCoSZener diodeSOT-233 pinsSeCoS
    What it is
    Zener diode
    Maker
    SeCoS
    Package
    SOT-23
    Pins
    3
    Source
    Manufacturer datasheet

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

  • BZX84B24-HFSOT-23Zener diode, 3 pins, ComchipZener diodeSOT-233 pinsComchip
    What it is
    Zener diode
    Maker
    Comchip
    Package
    SOT-23
    Pins
    3
    Details
    24 V 0.35 mW zener diode
    Source
    Manufacturer datasheet

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

  • BZX84C24SOT-23Zener diode, 3 pins, Taitron ComponentsZener diodeSOT-233 pinsTaitron Components
    What it is
    Zener diode
    Maker
    Taitron Components
    Package
    SOT-23
    Pins
    3
    Source
    Manufacturer datasheet

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

  • BZX84C24-CSOT-23Zener diode, 3 pins, SeCoSZener diodeSOT-233 pinsSeCoS
    What it is
    Zener diode
    Maker
    SeCoS
    Package
    SOT-23
    Pins
    3
    Source
    Manufacturer datasheet

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

  • BZX84C24-MSSOT-23Zener diode, 3 pins, MSKSEMIZener diodeSOT-233 pinsMSKSEMI
    What it is
    Zener diode
    Maker
    MSKSEMI
    Package
    SOT-23
    Pins
    3
    Source
    Manufacturer datasheet

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

  • BZX84C24AUSOT-23Zener diode, 3 pins, JieJieZener diodeSOT-233 pinsJieJie
    What it is
    Zener diode
    Maker
    JieJie
    Package
    SOT-23
    Pins
    3
    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.

P-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 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.

Codes that begin with Y9y

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

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