Chris, The following two papers might give some hints to your second question: Steven Sandler's "Spice uncovers regulator-stability problems" www.aeng.com/pdf/regulator.pdf Use op-amp injection for Bode analysis Bode analysis is an excellent way to measure small-signal stability and loop response in power-supply designs. Bode analysis monitors gain and phase of a control loop. http://www.reed-electronics.com/ednmag/article/CA450603?pubdate=9%2F16%2 F2004&spacedesc=designideas&nid=2018&rid=1851695780 Thanks & Best Regards Weisky Deng Component Engineer Component Reliability & Application Research Center Huawei Technologies Co.,LTD mailto: xddyw@xxxxxxxxxx tel: (+86)-0755-89653409 fax:(+86)-0755-89653428 ------------------------------------------------------------------ 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: //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: //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