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SMD code 49-

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.

61 parts are printed 49-

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.

  • AO6409ASOT-23-6P-channel MOSFET, 6 pins, Alpha & Omega SemiconductorP-channel MOSFETSOT-23-66 pinsAlpha & Omega Semiconductor
    What it is
    P-channel MOSFET
    Maker
    Alpha & Omega Semiconductor
    Package
    SOT-23-6
    Pins
    6
    Details
    P-channel MOSFET (8-60 V)
    Source
    Manufacturer datasheet

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

  • DTC043TEBSOT-416Digital transistor (NPN, resistors built in), 3 pins, ROHMDigital transistor (NPN, resistors built in)SOT-4163 pinsROHM
    What it is
    Digital transistor (NPN, resistors built in)
    Maker
    ROHM
    Package
    SOT-416
    Pins
    3
    Details
    NPN 100mA 50V Digital Transistor (Bias Resistor Built-in Transistor)
    Source
    Manufacturer datasheet

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

  • DTC043TMSOT-723Digital transistor (NPN, resistors built in), 3 pins, ROHMDigital transistor (NPN, resistors built in)SOT-7233 pinsROHM
    What it is
    Digital transistor (NPN, resistors built in)
    Maker
    ROHM
    Package
    SOT-723
    Pins
    3
    Details
    NPN 100mA 50V Digital Transistor (Bias Resistor Built-in Transistor)
    Source
    Manufacturer datasheet

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

  • DTC043TUBSOT-323Digital transistor (NPN, resistors built in), 3 pins, ROHMDigital transistor (NPN, resistors built in)SOT-3233 pinsROHM
    What it is
    Digital transistor (NPN, resistors built in)
    Maker
    ROHM
    Package
    SOT-323
    Pins
    3
    Details
    NPN 100mA 50V Digital Transistor (Bias Resistor Built-in Transistor)
    Source
    Manufacturer datasheet

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

  • EMBA2N10JSSSOT-23N-channel MOSFET, 3 pins, Excelliance MOSN-channel MOSFETSOT-233 pinsExcelliance MOS
    What it is
    N-channel MOSFET
    Maker
    Excelliance MOS
    Package
    SOT-23
    Pins
    3
    Details
    100 V, 2 A N-channel MOSFET
    Source
    Manufacturer datasheet

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

  • GALI-49+SOT-89RF amplifier (MMIC), 3 pins, Mini-CircuitsRF amplifier (MMIC)SOT-893 pinsMini-Circuits
    What it is
    RF amplifier (MMIC)
    Maker
    Mini-Circuits
    Package
    SOT-89
    Pins
    3
    Details
    MMIC amplifier, DC-5 GHz
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: RF amplifier.

  • GSFW02005SOT-883P-channel MOSFET, 3 pins, Good-ArkP-channel MOSFETSOT-8833 pinsGood-Ark
    What it is
    P-channel MOSFET
    Maker
    Good-Ark
    Package
    SOT-883
    Pins
    3
    Details
    P-channel MOSFET, 20 V
    Source
    Manufacturer datasheet

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

  • GSFW02009SOT-883P-channel MOSFET, 3 pins, Good-ArkP-channel MOSFETSOT-8833 pinsGood-Ark
    What it is
    P-channel MOSFET
    Maker
    Good-Ark
    Package
    SOT-883
    Pins
    3
    Details
    P-channel MOSFET, 20 V
    Source
    Manufacturer datasheet

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

  • PDTC123JUSOT-323Digital transistor (NPN, resistors built in), 3 pins, NexperiaDigital transistor (NPN, resistors built in)SOT-3233 pinsNexperia
    What it is
    Digital transistor (NPN, resistors built in)
    Maker
    Nexperia
    Package
    SOT-323
    Pins
    3
    Details
    50 V, 100 mA NPN resistor-equipped transistor; R1 = 2.2 kΩ, R2 = 47 kΩ
    Source
    Manufacturer datasheet

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

  • PMBFJ309SOT-23JFET, 3 pins, NXPJFETSOT-233 pinsNXP
    What it is
    JFET
    Maker
    NXP
    Package
    SOT-23
    Pins
    3
    Details
    N-channel silicon field-effect transistors
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: JFET.

  • RB162LAM-60SOD-128Schottky diode, 2 pins, ROHMSchottky diodeSOD-1282 pinsROHM
    What it is
    Schottky diode
    Maker
    ROHM
    Package
    SOD-128
    Pins
    2
    Details
    Schottky Barrier Diode
    Source
    Manufacturer datasheet

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

  • 4 more parts have no package on record
    • ET4559ETEKNot recordedNot recordedNot recordedETEK
      What it is
      Not recorded
      Maker
      ETEK
      Package
      Not recorded
      Pins
      Not recorded
      Source
      Manufacturer datasheet

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

    • GSEY5U4000ESD protection diode, Good-ArkESD protection diodeNot recordedNot recordedGood-Ark
      What it is
      ESD protection diode
      Maker
      Good-Ark
      Package
      Not recorded
      Pins
      Not recorded
      Details
      ESD protection diode, VRWM 4.8 V
      Source
      Manufacturer datasheet

      Is it dead? The meter test is below: TVS or ESD protection diode.

    • LEE-49+RF amplifier (MMIC), Mini-CircuitsRF amplifier (MMIC)Not recordedNot recordedMini-Circuits
      What it is
      RF amplifier (MMIC)
      Maker
      Mini-Circuits
      Package
      Not recorded
      Pins
      Not recorded
      Details
      MMIC amplifier, DC-5 GHz
      Source
      Manufacturer datasheet

      Is it dead? The meter test is below: RF amplifier.

    • RB162L-60TFSchottky diode, ROHMSchottky diodeNot recordedNot recordedROHM
      What it is
      Schottky diode
      Maker
      ROHM
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Schottky Barrier Diode (AEC-Q101 qualified)
      Source
      Manufacturer datasheet

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

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.

Digital transistor

Ohms range, part lifted. The datasheet gives the built-in resistors: R1 in series with the base, R2 from base to emitter.

Working, it reads

Base to emitter reads about R1 plus R2 either way round, about 20 kΩ on a 10 k and 10 k part, give or take their wide tolerance. Collector to emitter reads open. A part with no R2 reads a junction behind R1 one way instead.

Dead, it reads

  • Collector to emitter the same both ways, near 0 Ω with a continuous beep: shorted.
  • From the base, open or far above R1 plus R2: R1 has failed. Static damage shows here most often.
  • Base to emitter near 0 Ω: failed short.
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:
The readings depend on the resistor values, so an identical part elsewhere on the board is the surest reference. Measure it the same way.
Watch for:
On the diode range a good part with 10 kΩ resistors reads open on every pair, so a good part looks dead there. Use the ohms range.

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

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.

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.

RF amplifier

Voltage, board powered, on the output pin that the bias resistor or choke feeds.

Working, it reads

The output pin sits at the device voltage the datasheet gives, a few volts, below the supply.

Dead, it reads

  • Output pin at 0 V, or near 0 Ω to ground with the power off: shorted inside.
  • Output pin at the full supply voltage: open inside, no current flowing.
On the board:
Measured on the board with power on; the bias network is part of the reading.
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 figures depend on the part and its bias resistor. The datasheet gives both.

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.

JFET

Ohms range for drain to source, diode range for the gate, part lifted.

Working, it reads

Drain to source conducts both ways at a few hundred ohms, depending on the part, and some meters beep on it. The gate reads one junction to drain and to source, about 0.6 to 0.7 V, and open the other way.

Dead, it reads

  • The gate the same both ways to drain or source, near 0 V with a continuous beep: gate shorted.
  • Drain to source open: the channel has 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:
Drain to source resistance varies from part to part. An identical part elsewhere on the board shows what is normal.
Watch for:
A good channel can beep like a short between drain and source. That is normal; the gate junction says whether it has failed.

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.

Printed with a code easy to misread as 49-

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 49-

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 186 more parts.

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