Hi Roopesh, I have faced similar problem in the past and went to cadence for the support but did not worked out. With the AC caps in the cadence the P and N waveforms will not come as expect. Later I simulated using HSPICE with initial condition settings or else you need to run a long bits for the settled waveforms. Regards Pugal ________________________________ From: Roopesh Badala <roopesh.badala@xxxxxxxxx> To: "si-list@xxxxxxxxxxxxx" <si-list@xxxxxxxxxxxxx> Sent: Friday, 8 July 2011 4:54 PM Subject: [SI-LIST] trouble simulating with AC coupling capacitors in topology Hi All, I am trying to simulate a topology which has AC coupling capacitors in it. Using Cadence Allegro PCB SI tool set , i am unable to get the expected output. but when I simulate the same topology by removing the AC coupling capacitors in signal path, I get a perfect waveform. Is this a tool limitation..? can some body suggest me if they have faced similar issue. Thank you Roopesh ------------------------------------------------------------------ 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 technical documents are available at: http://www.si-list.net List archives are viewable at: //www.freelists.org/archives/si-list 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: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List technical documents are available at: http://www.si-list.net List archives are viewable at: //www.freelists.org/archives/si-list Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu