It is my understanding that the absolute maximum rating traditionally found on datasheets is a DC condition and not necessarily applicable to transients. We have found that our ASICs can tolerate transients higher than the DC absolute max specified on the datasheet. Some devices are now specify both DC and AC maximum conditions on their datasheets. Regards, Tim __________________________________ Timothy J. Nash, P.E. Honeywell, Inc. Defense & Space Electronic Systems 13350 U.S. Hwy 19 N M/S 825-1 Clearwater, FL 33764-7290 Office : 727-539-2437 Fax : 727-539-2183 Email : tim.j.nash@xxxxxxxxxxxxx -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of Bill.Cohen@xxxxxxxxxxxxxxxx Sent: Thursday, January 12, 2006 7:45 PM To: andrew.seddon@xxxxxxxxxxxx Cc: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Re: Overshoot / Undershoot Andrew, JEDEC has an overshoot/undershoot specification for DDR2 a 1.8V technology. Older technologies relied on an absolute voltage but the newer technologies work on an absolute maximum and an area (above/below power) of stress. This area limits the overshoot stress into a maximum stress for a period of time. The long time reliability of the gate oxide is at issue here and the duty cycle of the signal also comes into play. Look at the DDR2 datasheet (JEDEC.org) and look at the stress model they have for undershoot/overshoot of input signals. We have incorporated this model into our latest specifications. Best Regards, -------------------------------------------------------------- | Bill Cohen | Toshiba America Electronic Components | Mixed Signal Design Group -------------------------------------------------------------- "Andrew Seddon" <andrew.seddon@ca msig.co.uk> To Sent by: <si-list@xxxxxxxxxxxxx> si-list-bounce@fr cc eelists.org Subject [SI-LIST] Overshoot / Undershoot 01/12/2006 07:30 PM Please respond to andrew.seddon@cam sig.co.uk Hello, I was wondering if anybody had an idea of what is a typically acceptable bad but workable overshoot/undershoot on a 3.3V system? For example I see some memory IC's can take transients upto 5.5v where as the datasheet max is say +0.3. Obviously this figure is based on DC. I presume the major effect's of over/under shoot are to reduce working life of the IC and make the circuit potentially fail at temperature extremes? So when you guys analyse overshoot/undershoot how do you decide if it's acceptable? Kind regards, Andrew ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: http://www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org List archives are viewable at: http://www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: http://www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org List archives are viewable at: http://www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: http://www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org List archives are viewable at: http://www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu