# Diodes Identification - GP048 (S3) & GP138 (LT)

**URL:** <https://forum.digikey.com/t/diodes-identification-gp048-s3-gp138-lt/34349>\
**Category:** Discrete Semiconductor Products\
**Tags:** stmicroelectronics, diodes, circuit-protection, power, part-identification, transient-voltage-suppressors-tvs\
**Created:** [August 22, 2023, 9:49pm UTC](https://forum.digikey.com/t/diodes-identification-gp048-s3-gp138-lt/34349 "2023-08-22T21:49:29Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![oktabitt](https://avatars.discourse-cdn.com/v4/letter/o/b3f665/32.png) [@oktabitt](https://forum.digikey.com/u/oktabitt)\
**Post date:** [August 22, 2023, 9:49pm UTC](https://forum.digikey.com/t/diodes-identification-gp048-s3-gp138-lt/34349/1 "2023-08-22T21:49:29Z")

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Hello,  
I can’t find any datasheet for these diodes and also I can’t understand what means the destinator name “ **DM** 2”.

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**Author:** ![Kristof\_2649](https://sea2.discourse-cdn.com/digikey/user_avatar/forum.digikey.com/kristof_2649/32/2325_2.png) [@Kristof\_2649](https://forum.digikey.com/u/Kristof_2649)\
**Post date:** [August 22, 2023, 10:03pm UTC](https://forum.digikey.com/t/diodes-identification-gp048-s3-gp138-lt/34349/2 "2023-08-22T22:03:31Z")

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Hello,

Thank you for your inquiry.

I am having difficulty pulling up any information to diodes with those numbers associated.

Could you please advise where these are being referenced?

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**Author:** ![APDahlen](https://sea2.discourse-cdn.com/digikey/user_avatar/forum.digikey.com/apdahlen/32/40191_2.png) [@APDahlen](https://forum.digikey.com/u/APDahlen)\
**Post date:** [August 23, 2023, 1:59am UTC](https://forum.digikey.com/t/diodes-identification-gp048-s3-gp138-lt/34349/3 "2023-08-23T01:59:38Z")

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Hello oktabitt,

It’s often difficult to locate semiconductors as there are so many closely related numbers.

Please provide additional information about your product. A picture would be especially useful as we can sometimes obtain clues about the semiconductor. It may also be useful to identify the product including the manufacturer and model number.

Looking forward to your reply. With your additional clues someone in this community may be able to identify the component.

Best Wishes,

APDahlen

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**Author:** ![oktabitt](https://avatars.discourse-cdn.com/v4/letter/o/b3f665/32.png) [@oktabitt](https://forum.digikey.com/u/oktabitt)\
**Post date:** [August 23, 2023, 3:48pm UTC](https://forum.digikey.com/t/diodes-identification-gp048-s3-gp138-lt/34349/4 "2023-08-23T15:48:53Z")

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Hello, below you can see the components on the PCB.

 ![IMG_20230822_172558](https://global.discourse-cdn.com/digikey/original/3X/5/f/5faa34c3f439ad071b88c8e4ba68813eab5b0fab.jpeg)

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**Author:** ![David\_1528](https://sea2.discourse-cdn.com/digikey/user_avatar/forum.digikey.com/david_1528/32/47212_2.png) [@David\_1528](https://forum.digikey.com/u/David_1528)\
**Post date:** [August 23, 2023, 5:30pm UTC](https://forum.digikey.com/t/diodes-identification-gp048-s3-gp138-lt/34349/5 "2023-08-23T17:30:51Z")

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Hi [oktabitt](https://forum.digikey.com/u/oktabitt),

The larger one is an STMicroelectronics Schottky diode part number [STPS340S](https://www.digikey.com/en/products/detail/stmicroelectronics/STPS340S/603489) with part marking of **S34** , as seen on page 17 of the [datasheet](https://www.st.com/content/ccc/resource/technical/document/datasheet/bb/db/21/0c/04/d9/41/a5/CD00000844.pdf/files/CD00000844.pdf/jcr:content/translations/en.CD00000844.pdf).

The smaller one is an STMicroelectronics bi-polar TVS (transient voltage suppressor) diode part number [SM6T12CA](https://www.digikey.com/en/products/detail/stmicroelectronics/SM6T12CA/1039073) with part marking of **LT** , as seen on page 11 of the [datasheet](https://www.st.com/content/ccc/resource/technical/document/datasheet/6f/2d/a6/9e/56/51/48/15/CD00000725.pdf/files/CD00000725.pdf/jcr:content/translations/en.CD00000725.pdf).

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**Author:** ![Kristof\_2649](https://sea2.discourse-cdn.com/digikey/user_avatar/forum.digikey.com/kristof_2649/32/2325_2.png) [@Kristof\_2649](https://forum.digikey.com/u/Kristof_2649)\
**Post date:** [August 23, 2023, 5:32pm UTC](https://forum.digikey.com/t/diodes-identification-gp048-s3-gp138-lt/34349/6 "2023-08-23T17:32:00Z")

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David beat me to it…

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**Author:** ![oktabitt](https://avatars.discourse-cdn.com/v4/letter/o/b3f665/32.png) [@oktabitt](https://forum.digikey.com/u/oktabitt)\
**Post date:** [August 23, 2023, 9:06pm UTC](https://forum.digikey.com/t/diodes-identification-gp048-s3-gp138-lt/34349/7 "2023-08-23T21:06:40Z")

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Many thanks to all of you.