Single-chip systems save the power dissipation that would be required for chip-to-chip communication, resulting in compact, low-power solutions for battery-powered applications. This paper describes the design and measured performance of a fully-functional digital core with a low-jitter, on-chip, MEMS-LC clock reference. This chip has been fabricated in TSMC's 0.18mum MM/RF bulk CMOS process. Maximum power consumption of the complete microsystem is 48.78mW operating at 90MHz on a 1.8V power supply