crystal info
crystal info
(OP)
i am desinging a circuit with a freescale 9s12 mcu. I have a crystal that i want to use to provide the 8mhz clock.
i wanted to know how to calculate the caps (C) on the crystal to get the proper crystal setup.
i know you need to worry about trace capacitance and capacitance from the actual micro
the specs for the crystal i have is
load cap: 8pf
esr: 220 ohms
drive level: 10 micro Watts (500 micro Watts)
| |
| _ |
| | | | | |
-----| | | |-----
| | |_| | |
| |
--- ---
--- C --- C
| |
| |
gnd gnd
i wanted to know how to calculate the caps (C) on the crystal to get the proper crystal setup.
i know you need to worry about trace capacitance and capacitance from the actual micro
the specs for the crystal i have is
load cap: 8pf
esr: 220 ohms
drive level: 10 micro Watts (500 micro Watts)
| |
| _ |
| | | | | |
-----| | | |-----
| | |_| | |
| |
--- ---
--- C --- C
| |
| |
gnd gnd





RE: crystal info
Do a search on this board... I posted some useful theoretical and practical tips calculating crystal cap values and other such stuff just a few months ago.
RE: crystal info
http://www.eng-tips.com/viewthread.cfm?qid=94043
RE: crystal info
I agree with the 16pF capacitors, as stated, it is just that they are effectively in series with each other, the series connected pair being in parallel with the crystal.
RE: crystal info
|___ What he said... ;)