Introduction
The Si55x VCXO utilizes a unique architecture to provide VCXO functionality and performance in an industry standard 5x7 mm CLCC package. This unique architecture provides nearly any clock frequency from 10 MHz to 1.4 GHz and voltage control for closed-loop applications (phase-locked loops).

The basis for frequency synthesis is a single-frequency bulk-acoustic wave (BAW) AT-cut crystal resonator that offers tight frequency stability over temperature and well understood aging behavior. A CMOS IC based on Silicon Labs’ proprietary DSPLL™ technology provides the frequency translation from the crystal to the desired output frequency.
Voltage control is achieved via a ground-referenced analog-to-digital converter (VCADC) that dynamically adjusts the frequency synthesis.