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SMD code search: identify a part by its marking

1 part in DFN is printed 1524.

The only part printed 1524 in this package in our tables

PLR1524

What it is
ESD protection diode
Maker
ProTek Devices
Package
DFN
Pins
Not recorded
Details
Ultra Low Capacitance Asymmetrical TVS Array
Source
Manufacturer datasheet

Is it dead?

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.

Datasheetfor PLR1524, opens in a new tab

Was it this one?

8 more parts have codes that begin with 1524: none in DFN, 8 with no package on record

Codes that begin with 1524

For a marking with its end worn or burnt off. Each one shows its full printed code.

8 parts have no package on record. Nothing rules them out, so they stay.

  • ICS1524AMprinted 1524AMNot recordedNot recorded

    Printed 1524AM. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

    What it is
    Not recorded
    Maker
    Not recorded
    Package
    Not recorded
    Pins
    Not recorded
    Details
    Clock generator
    Source
    Published code list

    Is it dead?

    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.

  • LR31524BG-AG6printed 1524GLDO regulator, UnisonicLDO regulatorUnisonic

    Printed 1524G. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

    What it is
    LDO regulator
    Maker
    Unisonic
    Package
    Not recorded
    Pins
    Not recorded
    Details
    Linear voltage regulator IC: LDO, Dual out, Vout1/Vout2=1.5V/2.4V±0.5%, 150mA, +CE, H-free
    Source
    Published code list

    Is it dead?

    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.

  • LR31524BL-AG6printed 1524LLDO regulator, UnisonicLDO regulatorUnisonic

    Printed 1524L. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

    What it is
    LDO regulator
    Maker
    Unisonic
    Package
    Not recorded
    Pins
    Not recorded
    Details
    Linear voltage regulator IC: LDO, Dual out, Vout1/Vout2=1.5V/2.4V±0.5%, 150mA, +CE, L-free
    Source
    Published code list

    Is it dead?

    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.

  • SN74LS240printed LS240Texas InstrumentsNot recordedTexas Instruments

    Printed LS240. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

    What it is
    Not recorded
    Maker
    Texas Instruments
    Package
    Not recorded
    Pins
    Not recorded
    Details
    Octal Buffers and Line Drivers With 3-State Outputs
    Source
    Published code list

    Is it dead?

    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.

  • SN74LS241printed LS241Texas InstrumentsNot recordedTexas Instruments

    Printed LS241. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

    What it is
    Not recorded
    Maker
    Texas Instruments
    Package
    Not recorded
    Pins
    Not recorded
    Details
    Octal Buffers and Line Drivers With 3-State Outputs
    Source
    Published code list

    Is it dead?

    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.

  • SN74LS244printed LS244Texas InstrumentsNot recordedTexas Instruments

    Printed LS244. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

    What it is
    Not recorded
    Maker
    Texas Instruments
    Package
    Not recorded
    Pins
    Not recorded
    Details
    Octal Buffers and Line Drivers With 3-State Outputs
    Source
    Published code list

    Is it dead?

    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.

  • SN74LS245printed LS245Logic level translator, Texas InstrumentsLogic level translatorTexas Instruments

    Printed LS245. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

    What it is
    Logic level translator
    Maker
    Texas Instruments
    Package
    Not recorded
    Pins
    Not recorded
    Details
    Bus Transceivers Octal Bus
    Source
    Published code list

    Is it dead?

    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.

  • SN74LS245DWRprinted LS245Logic level translator, Texas InstrumentsLogic level translatorTexas Instruments

    Printed LS245. Only the start matches what you typed, so this fits only if the rest of the marking is worn off.

    What it is
    Logic level translator
    Maker
    Texas Instruments
    Package
    Not recorded
    Pins
    Not recorded
    Details
    Bus Transceivers Octal Bus
    Source
    Published code list

    Is it dead?

    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.

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One code, several parts

Marking codes are not unique. In the standard code book, 6H on a SOT-23 is an NPN transistor, a varicap, an N-channel JFET, two digital transistors, a 3.6 V voltage detector: six parts from five makers. So a search on WhatSMD (What SMD) shows the parts we hold under that code and under codes easily misread as it, with only the columns that tell them apart.

6Hon a SOT-23, in the code book
  • NPN transistor
  • Varicap
  • N-channel JFET
  • Digital transistor ×2
  • 3.6 V voltage detector

When more than one is left

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