Skip to content
WhatSMDSign in

SMD code 45

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.

8 parts are printed 45

Not sure which one you have?

Answer up to 4 quick questions and these 8 parts are ranked, with a meter test that settles it. It works on a dead part too.

  • BAS40-05SOT-23Schottky diode, 3 pins, Diotec
    What it is
    Schottky diode
    Maker
    Diotec
    Package
    SOT-23
    Pins
    3
    Details
    40 V surface-mount Schottky barrier diode, dual common anode
    Source
    From the manufacturer's datasheet

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

    Datasheetfor BAS40-05, opens in a new tab
  • DTC124XE3SOT-416Digital transistor (NPN, resistors built in), 3 pins, ROHM
    What it is
    Digital transistor (NPN, resistors built in)
    Maker
    ROHM
    Package
    SOT-416
    Pins
    3
    Details
    NPN digital transistor (bias resistor built-in); R1 = 22kOhm, R2 = 47kOhm
    Source
    From the manufacturer's datasheet

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

    Datasheetfor DTC124XE3, opens in a new tab
  • DTC124XEBSOT-416Digital transistor (NPN, resistors built in), 3 pins, ROHM
    What it is
    Digital transistor (NPN, resistors built in)
    Maker
    ROHM
    Package
    SOT-416
    Pins
    3
    Details
    NPN digital transistor (bias resistor built-in); R1 = 22kOhm, R2 = 47kOhm
    Source
    From the manufacturer's datasheet

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

    Datasheetfor DTC124XEB, opens in a new tab
  • DTC124XKASOT-23Digital transistor (NPN, resistors built in), 3 pins, ROHM
    What it is
    Digital transistor (NPN, resistors built in)
    Maker
    ROHM
    Package
    SOT-23
    Pins
    3
    Details
    NPN digital transistor (bias resistor built-in); R1 = 22kOhm, R2 = 47kOhm
    Source
    From the manufacturer's datasheet

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

    Datasheetfor DTC124XKA, opens in a new tab
  • DTC124XMSOT-723Digital transistor (NPN, resistors built in), 3 pins, ROHM
    What it is
    Digital transistor (NPN, resistors built in)
    Maker
    ROHM
    Package
    SOT-723
    Pins
    3
    Details
    NPN digital transistor (bias resistor built-in); R1 = 22kOhm, R2 = 47kOhm
    Source
    From the manufacturer's datasheet

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

    Datasheetfor DTC124XM, opens in a new tab
  • DTC124XU3SOT-323Digital transistor (NPN, resistors built in), 3 pins, ROHM
    What it is
    Digital transistor (NPN, resistors built in)
    Maker
    ROHM
    Package
    SOT-323
    Pins
    3
    Details
    NPN digital transistor (bias resistor built-in); R1 = 22kOhm, R2 = 47kOhm
    Source
    From the manufacturer's datasheet

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

    Datasheetfor DTC124XU3, opens in a new tab
  • DTC124XUBSOT-323Digital transistor (NPN, resistors built in), 3 pins, ROHM
    What it is
    Digital transistor (NPN, resistors built in)
    Maker
    ROHM
    Package
    SOT-323
    Pins
    3
    Details
    NPN digital transistor (bias resistor built-in); R1 = 22kOhm, R2 = 47kOhm
    Source
    From the manufacturer's datasheet

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

    Datasheetfor DTC124XUB, opens in a new tab
  • EIA-96:450603Precision resistor (EIA-96 code), 2 pins
    What it is
    Precision resistor (EIA-96 code)
    Maker
    Not recorded
    Package
    0603
    Pins
    2
    Details
    EIA-96 precision chip resistor, significand 28.7; the printed mark adds a multiplier letter (45A = 287 Ohm, 45B = 2.87 kOhm)
    Source
    Added by hand from a published table

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

    Datasheetfor EIA-96:45, opens in a new tab

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.

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.

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.

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 45

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 45

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 62 more parts.

Open this in the search to correct a character or try another package.