This thesis focuses on the design of a high input impedance sensor readout system based on a continuous-time sigma-delta modulator with finite-impulse-response digital-to-analog converter feedback.

Both the system-level and circuit-level design techniques of this system are investigated. The concept and design methods of finite-impulse-response digital-to-analog converters are introduced. The first integrator with source degeneration resistors and an input Gm-boosting cell is designed to achieve high input impedance and linearity. Both simulation and post-layout simulation results confirm the expected effective number of bits of 15 bits in the readout performance. The design is fabricated in a standard 180nm CMOS technology.