Let me reply just to you, not to the list. Please pass it on to HaiXiao. The circuit is a typical circuit for an XTAL. The feedback of 1 MOhm may = or maynot be good. Often much different values are used, like 500 Ohm, = much lower. This depends on the inverter logic family that you use to = make the oscillator. If the delay of the inverter is not modeled well, = your circuit may not oscillate.=20 David Pommerenke Dr. David Pommerenke Missouri University of Science and Technology (MST), former name: UMR 118 EECH, 301 W. 16th Street, Rolla, MO 65409-0040 573 341 4531, cell: 573 308 2019 -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] = On Behalf Of ? ? Sent: Wednesday, June 18, 2008 8:40 AM To: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Re: How to do crystal simulation Hi David and Haixiao =20 Thank you!=20 I just got the crystal internal circuit. It's L. C. R in serial and = parallel with a C. I will have a try in Hspice with a initialized capacitor or inductor.=20 The outside circuit is two capacitor( both of them is about 22ps) = connected crystal's output and input with a R(1Mohm) in parallel. I don't have ADS tool. So I can't use it. If necessory I will release = the Hspice simulation script tomorrow night. Then you can see the = electrical circuit clearly. I'm not sure whether it can run or not.=20 =20 =20 =20 "Pommerenke, David" <davidjp@xxxxxxx> =D0=B4=B5=C0=A3=BA Li, Your attached file was not delivered, but normally I just set initial = conditions on the capacitor or the inductor that is part of the XTAL = model. Dr. David Pommerenke Missouri University of Science and Technology (MST), former name: UMR 118 EECH, 301 W. 16th Street, Rolla, MO 65409-0040 573 341 4531, cell: 573 308 2019 =20 Did you add stimulus to start the spice simulation? For example, a 1ns pulse. ADS has more choice on crystal simulation. Check the ADS help on oscillators. Regards, Haixiao -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] = On Behalf Of ? ? Sent: Tuesday, June 17, 2008 8:35 AM To: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] How to do crystal simulation Hi all, I have a problem with crystal simulation. Please check the attached. I = can't get the crystal start to "shake". The frequency I want to get is = 25MHz. I didn't get the internal circuit for crystal. The Pspice model = seems didn't work. What shall I do? =20 --------------------------------- = =D1=C5=BB=A2=D3=CA=CF=E4=A3=AC=C4=FA=B5=C4=D6=D5=C9=FA=D3=CA=CF=E4=A3=A1 ------------------------------------------------------------------ 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: =20 //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 =20 ------------------------------------------------------------------ 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 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