SRC Forum - Message Replies
Forum: Reliability & Maintainability Questions and Answers
Topic: Reliability & Maintainability Questions and Answers
Topic Posted by: Reliability & Maintainability Forum
Organization: System Reliability Center
Date Posted: Mon Aug 31 12:47:36 US/Eastern 1998
Posted by: Richard Smith
Date posted: Fri May 25 14:27:59 US/Eastern 2001
Subject: SMT Ferrite Beads - What are people using in MIL-217 and Bellcore 332 Predictions ??
Can anybody provide me with a suggestion for a suitable component to use in a MIL-HDBK-217 or Bellcore TR-332 reliability prediction that would cover a surface mount ferrite or ferrite bead ? Unless I have overlooked something, so far I have not found anything similar apart from possibly a chip resistor as a very loose approximation.
Subject: Ferrite Bead Reliability
Reply Posted by: Bruce Dudley
Organization: Reliability Analysis Center
Date Posted: Tue May 29 15:16:18 US/Eastern 2001
The NPRD(non-electronic parts reliability data)resource book does not have a direct listing for ferrite bead, surface mount. The only item described is a connector ferrite bead used in a ground mobile condition with a failure rate of 0.88 failures per million miles. After reviewing the manufacturer's part descriptions, I concluded that perhaps a core coil inductor type of circuit could be substituted. The NPRD data book has information on core coil devices. The summary information looks like this:
Core Coil - Commercial - Ground Benign - 0.003 failures per million hours. The data base is extensive as over four billion hours with twelve failures were collected.