The Cyber-Spy.Com Usenet Archive Feeds Directly
From The Open And Publicly Available Newsgroup
This Group And Thousands Of Others Are Available
On Most IS NNTP News Servers On Port 119.
Cyber-Spy.Com Is NOT Responsible For Any Topic,
Opinions Or Content Posted To This Or Any Other
Newsgroup. This Web Archive Of The Newsgroup And
Posts Are For Informational Purposes Only.
Subject: Re: Unusual latchup problem
X-Newsreader: Microsoft Outlook Express 6.00.2800.1106
NNTP-Posting-Date: Wed, 06 Nov 2002 08:08:09 GMT
Organization: AT&T Broadband
Date: Wed, 06 Nov 2002 08:08:09 GMT
"Jean-Rene David" wrote in message
This is a circuit I didn't design but which I'm troubleshooting.
>Also, when the -12V *doesn't* latchup, it actually goes up to 0.7V for
>50-400ms after the +12V rise before coming back down again to -12V. The
>delay seems random.
>If anyone has any idea on 1) the possible cause of this problem or 2) a way
>to troubleshoot the problem or otherwise find the faulty device, I would
It sounds like power supply sequencing may be causing the problem.
Depending on the design of the op-amp it will prefer to have one supply
powered up first. If the supply sequencing is wrong it will frequently
cause latchup. To test this out try sequencing the supplies to see if
turning on the -12V supply first then the +12V will eliminate the problem.
If so then you may be able to fix the problem by tailoring the supply
Go Back To The Cyber-Spy.Com
Usenet Web Archive Index Of
The sci.electronics.design Newsgroup