A new kind of low-power multibit third order continuous-time lowpass /spl Sigma//spl Delta/ modulator

This paper presents the design of a multi-bit-third-order low pass sigma-delta modulator using a continuous-time (CT) loop filter. The goal is to reduce the power consumption and the area of the modulator. The new notion is to use a successive approximation (SA) A/D converter as 4-bit quantizer in the sigma-delta-modulator. Simulation results of the CT sigma-delta modulator show a 95 dB signal to noise ratio in a bandwidth of 50 kHz and oversampling ratio (OSR) of 32.