SMD part marking code

MAT38 · ‎2025-08-05

"Hello, could you please tell me what component corresponds to the SMD code 'DUJ' on this diode? It appears to be manufactured by STMicroelectronics and is mounted near the 12V power input on a hard drive circuit board."

Peter BENSCH · ‎2025-08-05

Welcome @MAT38, to the community!

I also assume that both visible diodes with the markings DUI and DUJ are TVS in SMA package. However, both are probably custom parts as my database, which goes back to the last millennium, has no entry for them. The closest markings are DUC (SMAJ6.5A-TR), DUH (SMAJ8.5A-TR) and DUK (SMAJ12A-TR), so I suspect they are unipolar TVS with a voltage of 9...12V - but the voltage may be completely different.

I'm sorry not to be able to give a more pleasant answer.

Good luck!
/Peter

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Peter BENSCH · ‎2025-08-05

Welcome @MAT38, to the community!

I also assume that both visible diodes with the markings DUI and DUJ are TVS in SMA package. However, both are probably custom parts as my database, which goes back to the last millennium, has no entry for them. The closest markings are DUC (SMAJ6.5A-TR), DUH (SMAJ8.5A-TR) and DUK (SMAJ12A-TR), so I suspect they are unipolar TVS with a voltage of 9...12V - but the voltage may be completely different.

I'm sorry not to be able to give a more pleasant answer.

Good luck!
/Peter

In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.