Phase locked loop-based clock synthesizer for reconfigurable analog-to-digital converters

Abstract

This paper presents the complete design of a phase locked loop-based clock synthesizer for reconfigurable analog-to-digital converters. The synthesizer was implemented in TSMC 65 nm CMOS process technology and the presented results were obtained from extracted layout view with parasitics. The synthesizer generates clock frequencies ranging from 40 to 230 MHz considering a reference frequency of 10 MHz and a supply voltage of 1.2 V. Worst case current consumption is 634 mu W, settling time is 6 mu s, maximum jitter is 1.3 ns in a 0.037 mm^2 area. Performance was validated in a test Sigma Delta Modulator with bandwidths of 200 kHz, 500 kHz and 2 MHz, and oversampling frequencies of 40, 60 and 80 MHz respectively, with negligible signal-to-noise ratio degradation compared to an ideal clock.