A highly stable CMOS Self-Compensated Oscillator (SCO) based on an LC tank temperature Null concept

Abstract

A highly stable all silicon Self-Compensated Oscillator (SCO) reference source is presented. Self compensation across temperature is achieved using a newly discovered phenomenon in LC-tanks named the Temperature Null (TNULL) which has been described and briefly analyzed. A quadrature oscillator architecture has been used to implement the SCO in a 0.18μm CMOS technology. The SCO has on-chip infrastructure facilitating low cost trimming and frequency calibration at room temperature. Excellent frequency stability of ±50ppm has been measured across temperature (0 - 70°C), 3.0 - 3.6V supply and 1 - 15pF load. The SCO has a programmable frequency range of 1 - 133MHz, consumes 7.1mA at 25MHz and has an RMS period jitter of 2ps at 125MHz.