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SMD code 508

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.

508 on a chip capacitor

0.5 pF

0.5 pF capacitor

50 followed by the multiplier 8, in picofarads: 0.5 pF. Printed this way on film and larger ceramic capacitors; small chip ceramics are usually not printed at all.

Check it with a meter

Lift one end and measure it on a capacitance range. A good one reads close to 0.5 pF. In circuit the meter also sees everything connected across it, so the reading means little until it is out. A failed one usually reads near 0 Ω, or a steady low resistance, on the ohms range, often from a crack. On the board a shorted capacitor shorts its whole rail. A failed reading does not change what to fit: the marking still says 0.5 pF.

On a transistor or diode body (SMA, SOT-23-5, SMC), 508 is a part code instead. Those parts are listed below.

3 parts are printed 508

Not sure which one you have?

Answer up to 4 quick questions and these 3 parts are ranked, with a meter test that settles it. It works on a dead part too.

  • PLR0508DFNESD protection diode, ProTek DevicesESD protection diodeDFNNot recordedProTek Devices
    What it is
    ESD protection diode
    Maker
    ProTek Devices
    Package
    DFN
    Pins
    Not recorded
    Details
    Ultra Low Capacitance Steering Diode/TVS Array
    Source
    Manufacturer datasheet

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

    Datasheetfor PLR0508, opens in a new tab
  • R1191N108BSOT-23-5LDO regulator, 5 pins, RicohLDO regulatorSOT-23-55 pinsRicoh
    What it is
    LDO regulator
    Maker
    Ricoh
    Package
    SOT-23-5
    Pins
    5
    Details
    Linear voltage regulator IC: LDO, 10.8V±1.5%, 300mA, +CE, ECO
    Source
    Published code list

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

  • SST508SOT-233 pins, CalogicNot recordedSOT-233 pinsCalogic
    What it is
    Not recorded
    Maker
    Calogic
    Package
    SOT-23
    Pins
    3
    Details
    Current regulator diode
    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.

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.

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.

Printed with a code easy to misread as 508

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 8 more parts.

Did you find your part?

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