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WhatSMDSign in

SMD marking

K5in SOT-23-6

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.

Not sure which one you have?

Answer up to 4 quick questions and these 2 parts are ranked, with a meter test that settles it. It works on a dead part too.

The only part printed K5 in this package in our tables

PESD5V0S4UD

What it is
ESD protection diode
Maker
Nexperia
Package
SOT-23-6
Pins
6
Details
Quadruple ESD protection diode array
Source
From the manufacturer's 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:
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 PESD5V0S4UD, opens in a new tab

Printed with a code easy to misread

This part is printed with a character that is easy to misread as what you typed. The odd one out is marked on each.

  • TPS7A20105PDQNprinted KSLDO regulator, 4 pins, Texas Instruments

    Printed KS on the part. Easy to misread as K5. Check that character with a loupe before you order anything.

    What it is
    LDO regulator
    Maker
    Texas Instruments
    Package
    Not recorded
    Pins
    4
    Details
    300mA, Ultra-Low-Noise, Low-IQ, High PSRR LDO
    Source
    From the manufacturer's datasheet

    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.

    Datasheetfor TPS7A20105PDQN, opens in a new tab

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