[SI-LIST] Re: How to do crystal simulation

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

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