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

• From: "Beal, Weston" <Weston_Beal@xxxxxxxxxx>
• To: <si-list@xxxxxxxxxxxxx>
• Date: Wed, 18 Jun 2008 07:44:58 -0700

=20
Based on your description of you circuit, I would not expect it to =
oscillate. An oscillator needs some amplification element and all of you =
circuit is passive elements. You should find a reference on basic =
oscillator design.
http://en.wikipedia.org/wiki/Pierce_oscillator

It sounds like you got your circuit from an IC design guide that =
suggested a circuit for the input to a clock generator. The part you =
missed is that the IC itself provides the amplifier that you are missing =

Regards,
Weston

-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] =
On Behalf Of ? ?
Sent: Wednesday, June 18, 2008 6:40 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
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