Analysis and Optimization of Parasitics-Induced Peak Frequency Shift in Gain-Boosted N-Path Switched-Capacitor Bandpass Filter

This letter proposes a $C/g_{m}$ method for analyzing the peak frequency shift caused by parasitic parameters in gain-boosted N-path switched-capacitor bandpass filter (GB-BPF). This method eliminates the device width variable, addressing the interdependencies among various parameters in GB-BPF. Numerical solution for peak frequency shift is obtained, and the impact of each variable on frequency shift is accurately quantified. Using the proposed $C/g_{m}$ variable, the optimal bias voltage is determined to minimize the peak frequency shift for same parasitic parameters. Additionally, optimization strategies for adjusting the filter capacitance and switching frequency are proposed. Finally, a GB-BPF is implemented in a 90-nm CMOS process. The accuracy of the analysis is verified by comparing the measured and simulated results with the theoretically derived results.