A Low Distortion CMOS Bootstrapped Switch

Libo Qian, Zhangming Zhu, Yintang Yang

Abstract: This paper presents a novel low distortion CMOS bootstrapped switch that adopts a "source track" technique to track the real source terminal of the sampling switch. This technique improves nonlinear distortion due to variation of the gate overdrive and the threshold voltage in conventional switches, acquiring a precise sampling of signal. Based on the SMIC 0.18 mum standard CMOS process, the proposed switch has been simulated at 200 MSPS. The simulation results show the spurious-free dynamic range (SFDR) is 73.6 dB and total harmonic distortion (THD) is -79.8 dB.