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SMD code 37-

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.

47 parts are printed 37-

Not sure which one you have?

Answer up to 4 quick questions and these 47 parts are ranked, with a meter test that settles it. It works on a dead part too.

  • BZX384-A18SOD-323Zener diode, 2 pins, NexperiaZener diodeSOD-3232 pinsNexperia
    What it is
    Zener diode
    Maker
    Nexperia
    Package
    SOD-323
    Pins
    2
    Source
    Manufacturer datasheet

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

  • CHEMD37GPSOT-563Complementary transistor pair (NPN and PNP), 6 pins, ChenmkoComplementary transistor pair (NPN and PNP)SOT-5636 pinsChenmko
    What it is
    Complementary transistor pair (NPN and PNP)
    Maker
    Chenmko
    Package
    SOT-563
    Pins
    6
    Details
    Dual Digital Silicon Transistor, 50 V, 70 mA
    Source
    Manufacturer datasheet

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

  • DTA043EEBSOT-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.

  • DTA043EMSOT-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.

  • DTA043EUBSOT-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.

  • RB060MM-60SOD-123FSchottky diode, 2 pins, ROHMSchottky diodeSOD-123F2 pinsROHM
    What it is
    Schottky diode
    Maker
    ROHM
    Package
    SOD-123F
    Pins
    2
    Details
    Schottky Barrier Diode
    Source
    Manufacturer datasheet

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

  • RB060MM-60TFSOD-123FSchottky diode, 2 pins, ROHMSchottky diodeSOD-123F2 pinsROHM
    What it is
    Schottky diode
    Maker
    ROHM
    Package
    SOD-123F
    Pins
    2
    Details
    Schottky Barrier Diode
    Source
    Manufacturer datasheet

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

  • EIA-96:370603Precision 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 37 stands for 237 in the E96 table; the printed mark adds a multiplier letter (37A = 237 Ohm, 37B = 2.37 kOhm)
    Source
    Added by hand from a published table

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

  • BL8063CKETR37DFNLDO regulator, Shanghai BellingLDO regulatorDFNNot recordedShanghai Belling
    What it is
    LDO regulator
    Maker
    Shanghai Belling
    Package
    DFN
    Pins
    Not recorded
    Details
    Linear voltage regulator IC: LDO, 3.7V±2%, 300mA, +CE
    Source
    Published code list

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

  • BL8563CKETR37DFNLDO regulator, Shanghai BellingLDO regulatorDFNNot recordedShanghai Belling
    What it is
    LDO regulator
    Maker
    Shanghai Belling
    Package
    DFN
    Pins
    Not recorded
    Details
    Linear voltage regulator IC: LDO, 3.7V±2%, 300mA, +CE
    Source
    Published code list

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

  • 5 more parts have no package on record
    • BFCN-2275+RF filter, Mini-CircuitsRF filterNot recordedNot recordedMini-Circuits
      What it is
      RF filter
      Maker
      Mini-Circuits
      Package
      Not recorded
      Pins
      Not recorded
      Details
      LTCC filter, 2170-2380 MHz
      Source
      Manufacturer datasheet

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

    • ET3176Load switch, ETEKLoad switchNot recordedNot recordedETEK
      What it is
      Load switch
      Maker
      ETEK
      Package
      Not recorded
      Pins
      Not recorded
      Source
      Manufacturer datasheet

      Is it dead? The meter test is below: Load switch.

    • SGM2037-3.6XUDX6GLDO regulator, 6 pins, SG MicroLDO regulatorNot recorded6 pinsSG Micro
      What it is
      LDO regulator
      Maker
      SG Micro
      Package
      Not recorded
      Pins
      6
      Details
      3.6 V output, 500mA, Low Noise, Very Low Dropout Bias Rail CMOS Voltage Regulator
      Source
      Manufacturer datasheet

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

    • SGM41106A-452O31YXDH4GBattery 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.

    • ADP124ARHZ-1.8-R78 pins, Analog DevicesNot recordedNot recorded8 pinsAnalog Devices
      What it is
      Not recorded
      Maker
      Analog Devices
      Package
      Not recorded
      Pins
      8
      Details
      equivalent [1.8V LDO]
      Source
      Published code list

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

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.

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.

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.

Bipolar transistor pair

Diode range, part lifted. Test each transistor on its own pins, as the datasheet's pinout gives them.

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.

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.

Load switch

Voltage, board powered, black probe on ground.

Working, it reads

Switched on, the output pin sits at the input voltage. Switched off, it sits near 0 V.

Dead, it reads

  • Output at the input voltage while switched off: the pass element has shorted.
  • Input present and switched on, no output: failed open, or shut down into a shorted load. Power off and measure output to ground.
On the board:
An output near 0 Ω to ground is usually the load. Lift the output pin to see which.
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 pinout and whether the enable is active high or low differ between parts. 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.

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.

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.

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 37-

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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