TECHNET Archives

February 2000

TechNet@IPC.ORG

Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
Robert K Veale <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Thu, 3 Feb 2000 15:55:49 -0500
Content-Type:
text/plain
Parts/Attachments:
text/plain (31 lines)
We have experienced several failures of multilayer chip capacitors in
120Vrms AC applications.  These are 500V and 1000V DC rated,  X7R, .01uF
multilayer ceramic chip capacitors.  After some investigation, we see that
some supplier's parts survive and another supplier's devices have a high
failure rate.  We have ruled out causes such as flexure cracks and thermal
cracks.  It appears that the dielectric is degrading and breaking down
under AC conditions but is OK under DC conditions.  The peak-to-peak AC
voltage is well within the DC rating of the part.

Has anyone observed MLC failures with AC line voltage but not DC voltage?
Is there any selection guidelines or other know-how for choosing a ceramic
capacitor for AC across-the-line applications?

Bob Veale
Rockwell Automation
Cleveland Ohio

##############################################################
TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c
##############################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in
the body:
To subscribe:   SUBSCRIBE TECHNET <your full name>
To unsubscribe:   SIGNOFF TECHNET
##############################################################
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information.
If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or
847-509-9700 ext.5365
##############################################################

ATOM RSS1 RSS2