Reprogrammable, wide tuning range 1.6 GHz CMOS VCO with low phase noise variation

Abstract

It is difficult to obtain simultaneously a large tuning range, low phase noise, and small phase noise variation, particularly while accommodating manufacturing and packaging tolerances. This work describes the first use of native EPROM devices (available in every standard CMOS technology) and switched reactances to relax these tradeoffs. In addition to permitting post-packaging compensation for manufacturing variations, the inherent reprogrammability of these cells also enables the rapid prototyping and optional reconfiguration of RF and mixed-signal systems. This technology allows the realization of a fully-integrated oscillator in 0.25 μm CMOS with a phase noise variation of under 10 dB (compared with 40 dB variation in a conventional implementation) over a 1.25 GHz to 1.92 GHz (42%) tuning range. The oscillator consumes 23 mW from a 3 V supply while exhibiting a phase noise of better than -93dBc/Hz at 100 kHz offset from a nominal 1.58 GHz center frequency.