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MAT38
Visitor II
August 5, 2025
Solved

SMD part marking code

  • August 5, 2025
  • 1 reply
  • 259 views

"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."

Best answer by Peter BENSCH

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

1 reply

Peter BENSCH
Peter BENSCHBest answer
Technical Moderator
August 5, 2025

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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