Rahul, Actually, your question is generic: Should I pay attention to max_flight time with a fast driver? Should I pay attention to min_flight time with a slow driver? The answer is irrespective of the SI tool being used. The answer to these questions is a qualified yes. If your circuit is poorly terminated, or impedances are poorly matched, a fast driver can cause enough ringing that the "fast" case will have the longest settle time. This is especially true with large, poorly designed packages, as any of the SI veterans can tell you. Slow driver / min_flight is usually not a problem, and in certain cases should be disregarded. The reasoning is somewhat complex, and depends on how you're doing your timing budgets. In my experience, I've run into cases (with large capacitive reference loads) where the slow driver / min_flight was the shortest flight time of all, causing an apparent timing violation that we disregarded on closer inspection. Hope that helps, Todd. Todd Westerhoff SI Engineer Hammerhead Networks 5 Federal Street Billerica, MA 01821 twester@xxxxxxxxxxx ph: 978-671-5084 -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]On Behalf Of whiz kid Sent: Monday, August 06, 2001 11:14 PM To: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Question about Simulation in Spectraquest Hi Gurus, I have a question about the usability of the values that spectraquest spits when doing a flight time simulation. When I am doing a simulation with a fast driver, fast transmission line, and fast reciever I am more concerned with the Min switch time (Min flight time). Is the settle time (max flight time) that SQ displays a use ful parameter here??. Because to find the max flight time u make use of the slow driver, slow line, slow reciever. Am I missing some thing in how to interpret the values. Regards, Rahul. __________________________________________________ Do You Yahoo!? Make international calls for as low as $.04/minute with Yahoo! Messenger http://phonecard.yahoo.com/ ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List archives are viewable at: //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 For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List archives are viewable at: //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