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SMD code 59-

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.

59 parts are printed 59-

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.

  • BZX84-A5V6SOT-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
    5.6 V ±1% voltage regulator (Zener) diode
    Source
    Manufacturer datasheet

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

  • BZX584C5V6SOD-523Zener diode, 2 pins, Yangjie Electronic TechZener diodeSOD-5232 pinsYangjie Electronic Tech
    What it is
    Zener diode
    Maker
    Yangjie Electronic Tech
    Package
    SOD-523
    Pins
    2
    Source
    Manufacturer datasheet

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

  • BZX584C5V6QSOD-523Zener diode, 2 pins, Yangjie Electronic TechZener diodeSOD-5232 pinsYangjie Electronic Tech
    What it is
    Zener diode
    Maker
    Yangjie Electronic Tech
    Package
    SOD-523
    Pins
    2
    Source
    Manufacturer datasheet

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

  • DTA024XEBSOT-416Digital transistor (PNP, resistors built in), 3 pins, ROHMDigital transistor (PNP, resistors built in)SOT-4163 pinsROHM
    What it is
    Digital transistor (PNP, resistors built in)
    Maker
    ROHM
    Package
    SOT-416
    Pins
    3
    Details
    PNP -100mA -50V Digital Transistor (Bias Resistor Built-in Transistor)
    Source
    Manufacturer datasheet

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

  • DTA024XMSOT-723Digital transistor (PNP, resistors built in), 3 pins, ROHMDigital transistor (PNP, resistors built in)SOT-7233 pinsROHM
    What it is
    Digital transistor (PNP, resistors built in)
    Maker
    ROHM
    Package
    SOT-723
    Pins
    3
    Details
    PNP -100mA -50V Digital Transistor (Bias Resistor Built-in Transistor)
    Source
    Manufacturer datasheet

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

  • DTA024XUBSOT-323Digital transistor (PNP, resistors built in), 3 pins, ROHMDigital transistor (PNP, resistors built in)SOT-3233 pinsROHM
    What it is
    Digital transistor (PNP, resistors built in)
    Maker
    ROHM
    Package
    SOT-323
    Pins
    3
    Details
    PNP -100mA -50V Digital Transistor (Bias Resistor Built-in Transistor)
    Source
    Manufacturer datasheet

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

  • GALI-59+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.

  • MM5Z5V6-CSOD-523Zener diode, 2 pins, SeCoSZener diodeSOD-5232 pinsSeCoS
    What it is
    Zener diode
    Maker
    SeCoS
    Package
    SOD-523
    Pins
    2
    Source
    Manufacturer datasheet

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

  • MT5Z5V6-CSOD-523Zener diode, 2 pins, SeCoSZener diodeSOD-5232 pinsSeCoS
    What it is
    Zener diode
    Maker
    SeCoS
    Package
    SOD-523
    Pins
    2
    Source
    Manufacturer datasheet

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

  • EIA-96:590603Precision resistor (EIA-96 code), 2 pinsPrecision resistor (EIA-96 code)06032 pinsNot recorded
    What it is
    Precision resistor (EIA-96 code)
    Maker
    Not recorded
    Package
    0603
    Pins
    2
    Details
    EIA-96 precision chip resistor, code 59 stands for 402 in the E96 table; the printed mark adds a multiplier letter (59A = 402 Ohm, 59B = 4.02 kOhm)
    Source
    Added by hand from a published table

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

  • 5 more parts have no package on record
    • LEE-59+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.

    • LRC1043-04DT1GESD protection diode, LRCESD protection diodeNot recordedNot recordedLRC
      What it is
      ESD protection diode
      Maker
      LRC
      Package
      Not recorded
      Pins
      Not recorded
      Details
      ESD protection diode, VRWM 3.3 V, IR @VRWM 1 μA, VBR Min 5.6 V
      Source
      Manufacturer datasheet

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

    • S-LRC1043-04DT1GESD protection diode, LRCESD protection diodeNot recordedNot recordedLRC
      What it is
      ESD protection diode
      Maker
      LRC
      Package
      Not recorded
      Pins
      Not recorded
      Details
      ESD protection diode, VRWM 3.3 V, IR @VRWM 1 μA, VBR Min 5.6 V
      Source
      Manufacturer datasheet

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

    • SGM892B-1.8XUDH4GVoltage supervisor, 4 pins, SG MicroVoltage supervisorNot recorded4 pinsSG Micro
      What it is
      Voltage supervisor
      Maker
      SG Micro
      Package
      Not recorded
      Pins
      4
      Details
      Standard CMOS Voltage Detector ICs
      Source
      Manufacturer datasheet

      Is it dead? The meter test is below: Integrated circuit.

    • SGM41106A-455O62YXDH4GBattery protection IC, 4 pins, SG MicroBattery protection ICNot recorded4 pinsSG Micro
      What it is
      Battery protection IC
      Maker
      SG Micro
      Package
      Not recorded
      Pins
      4
      Details
      Primary Protector and Switch with Shipping Mode for Tiny Li+/Poly Battery
      Source
      Manufacturer datasheet

      Is it dead? The meter test is below: Integrated circuit.

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.

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.

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.

Integrated circuit

Voltage with the board powered; ohms from each pin to ground with it off.

Working, it reads

Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.

Dead, it reads

  • A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
  • Supply present, output stuck: failed, or its load has.
On the board:
A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
Compare:
The surest reference is the same IC on a working board, measured pin by pin.
Watch for:
Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.

A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

Resistor

Ohms range, across it, power off.

Working, it reads

Its marked value, within tolerance. On the board it reads the same or lower, because everything around it sits in parallel.

Dead, it reads

  • Open: burnt, cracked, or eaten through by sulphur. The commonest failure.
  • Well above its marked value: drifted high.
  • On the board, clearly higher than its marked value: it has failed, since the board can only pull a reading down.
On the board:
A reading lower than marked on the board proves nothing; lift one end. A reading higher than marked is a fault even on the board.
Compare:
The same position on another channel usually carries the same value, and so does the matching part on another board.
Watch for:
A burnt resistor usually means the part it feeds pulled too much. Find that before fitting a new one, or it burns too. The marking, not the reading, says what to fit.

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 59-

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

Codes not listed here are printed on 2 more parts.

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