1.8V to 3.3V PicoPLL

47745 Fremont Blvd., Fremont, California 94538 Tel (510) 492-0990 Fax (510) 492-0991 www.phaselink.com Rev 2/25/07 Page 7

Crystal Tuning Circuit

Series and parallel capacitors used to fine tune the crystal load to the circuit load .

CST – Series Capacitor, used to lower circuit load to match crystal load . Raises frequency

offset. This can be eliminated by using a crystal with a Cload of equal or greater value than the

oscillator.

CPT – Parallel Capacitors , Used to raise the circuit load to match the crystal load. Lowers

frequency offset .

Crystal

XIN

1

8

XOUT

Cpt

Cpt

Cst