Too bad we can't pop open/disolve the package and take a look at the die and *see* what the failure mode was: punch-through, metal migtration, over temp, manufacturing defect, bond wire ??? We used to do that on our own RF power transistors when I worked at Heathkit in Benton Harbor (actually St. Joseph!). We did it VERY carefully as the packages were BeO (Berillium Oxide is toxic, we didn't *break* these open however, there *is* a trick to doing it). RF Jim "Our ability to manufacture fraud has exceeded our ability to detect it." - Al Pacino as Viktor Taransky in the movie 'Simone' ----- Original Message ----- From: "Jinx" To: Sent: Friday, August 23, 2002 6:53 PM Subject: Re: [EE]: Crowbar protection > > 14 V eh? > > > > Sounds like automotive mains. > > Close - gel cell > > > A nasty environ - I lost LM555's when powered > > directly off automotive mains YEARS ago - on > > one of my first projects! > > > > Solution was to add a real - sorry, an "RF" term > > there - add a series resistor along with a shunt > > electrolytic cap - any 'spikes' are met by (dropped > > across) the R (chosen based on some maths) against > > the influence of the electrolytic cap ... > > No problem with spikes or anything else untoward AFAICT, this > particular regulator just decided to give up its day job > -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body