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SMD code TF-

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.

56 parts are printed TF-

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.

  • BAV199STB6SOT-563Switching diode, 6 pins, PanjitSwitching diodeSOT-5636 pinsPanjit
    What it is
    Switching diode
    Maker
    Panjit
    Package
    SOT-563
    Pins
    6
    Source
    Manufacturer datasheet

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

  • BFU530XSOT-143RF transistor, 4 pins, NXPRF transistorSOT-1434 pinsNXP
    What it is
    RF transistor
    Maker
    NXP
    Package
    SOT-143
    Pins
    4
    Details
    NPN wideband silicon RF transistor
    Source
    Manufacturer datasheet

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

  • BZX84J-B62SOD-323Zener diode, 2 pins, NexperiaZener diodeSOD-3232 pinsNexperia
    What it is
    Zener diode
    Maker
    Nexperia
    Package
    SOD-323
    Pins
    2
    Pinout
    • 1 cathode
    • 2 anode
    Details
    62 V ±2% voltage regulator (Zener) diode
    Source
    Manufacturer datasheet

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

  • MM3Z6V8SSOD-323Zener diode, 2 pins, Galaxy MicroelectronicsZener diodeSOD-3232 pinsGalaxy Microelectronics
    What it is
    Zener diode
    Maker
    Galaxy Microelectronics
    Package
    SOD-323
    Pins
    2
    Details
    6.8V, 400mW, Surface Mount Zener Diodes
    Source
    Manufacturer datasheet

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

  • MM5Z6V8SSOD-523Zener diode, 2 pins, onsemiZener diodeSOD-5232 pinsonsemi
    What it is
    Zener diode
    Maker
    onsemi
    Package
    SOD-523
    Pins
    2
    Details
    Zener Voltage Regulators MM5ZxxxST1G Series, SZMM5ZxxxST1G Series
    Source
    Manufacturer datasheet

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

  • MMSZ4681SOD-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.

  • MMSZ4681-GSOD-123Zener diode, 2 pins, VishayZener diodeSOD-1232 pinsVishay
    What it is
    Zener diode
    Maker
    Vishay
    Package
    SOD-123
    Pins
    2
    Details
    2.4 V Zener diode
    Source
    Manufacturer datasheet

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

  • NTA4015NSOT-416N-channel MOSFET, 3 pins, onsemiN-channel MOSFETSOT-4163 pinsonsemi
    What it is
    N-channel MOSFET
    Maker
    onsemi
    Package
    SOT-416
    Pins
    3
    Details
    Small Signal MOSFET
    Source
    Manufacturer datasheet

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

  • NTJD5121NSOT-363Dual N-channel MOSFET, 6 pins, onsemiDual N-channel MOSFETSOT-3636 pinsonsemi
    What it is
    Dual N-channel MOSFET
    Maker
    onsemi
    Package
    SOT-363
    Pins
    6
    Details
    MOSFET - Power, Dual, N-Channel With ESD Protection
    Source
    Manufacturer datasheet

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

  • RS3217F-2.9XUTDN4DFNLDO regulator, RunicLDO regulatorDFNNot recordedRunic
    What it is
    LDO regulator
    Maker
    Runic
    Package
    DFN
    Pins
    Not recorded
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: Voltage regulator.

  • TMM3Z6V8SSOD-323Zener diode, 2 pins, Galaxy MicroelectronicsZener diodeSOD-3232 pinsGalaxy Microelectronics
    What it is
    Zener diode
    Maker
    Galaxy Microelectronics
    Package
    SOD-323
    Pins
    2
    Details
    6.8V, 400mW, Surface Mount Zener Diodes
    Source
    Manufacturer datasheet

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

  • 4 more parts have no package on record
    • LNTA4001NT1GN-channel MOSFET, LRCN-channel MOSFETNot recordedNot recordedLRC
      What it is
      N-channel MOSFET
      Maker
      LRC
      Package
      Not recorded
      Pins
      Not recorded
      Details
      MOSFET, N-Channel(with ESD), VDSS 20 V, VGS 10 V
      Source
      Manufacturer datasheet

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

    • NCP105AMX280LDO regulator, onsemiLDO regulatorNot recordedNot recordedonsemi
      What it is
      LDO regulator
      Maker
      onsemi
      Package
      Not recorded
      Pins
      Not recorded
      Details
      LDO Regulator - High PSRR
      Source
      Manufacturer datasheet

      Is it dead? The meter test is below: Voltage regulator.

    • NCV8177AMTW330LDO regulator, onsemiLDO regulatorNot recordedNot recordedonsemi
      What it is
      LDO regulator
      Maker
      onsemi
      Package
      Not recorded
      Pins
      Not recorded
      Details
      Linear Voltage Regulator, Fast Transient Response, 500 mA with Enable
      Source
      Manufacturer datasheet

      Is it dead? The meter test is below: Voltage regulator.

    • S-LNTA4001NT1GN-channel MOSFET, LRCN-channel MOSFETNot recordedNot recordedLRC
      What it is
      N-channel MOSFET
      Maker
      LRC
      Package
      Not recorded
      Pins
      Not recorded
      Details
      MOSFET, N-Channel(with ESD), VDSS 20 V, VGS 10 V
      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.

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.

Bipolar transistor

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

Working, it reads

From the base, one probe colour 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.

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.

Voltage regulator

Voltage, board powered, black probe on ground. Then ohms with the power off.

Working, it reads

Input pin at the supply, output pin at its rated voltage, and the enable pin high if it has one.

Dead, it reads

  • Output equal to the input: the pass element has shorted. Everything after it may have taken the full input.
  • Input present, enable high, no output: failed open, or holding itself off into a shorted load. Power off and measure output to ground.
  • Power off, input to output near 0 Ω: shorted.
On the board:
An output at 0 V is often a shorted load with the regulator in current limit. Lift the output pin: if the short stays on the board, the regulator may be fine.
Compare:
The same regulator on another rail or another board shows the right voltages and the right resistances.
Watch for:
Makers put input, output and ground on different pins in the same package, so take them from this part's datasheet. Diode or ohms readings between its pins say little; check it powered.

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.

Printed with a code easy to misread as TF-

One character differs, and it is one that is easy to confuse under a lamp. Each code has a page of its own.

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