A2.2 MHz,8.3 mW Multi-bit Continuous-Time Sigma-Delta Modulator

A 2.2 MHz,8.3 mW continuous-time Sigma-delta (CT Σ-Δ) modulator is designed,which targets wireless communication applications.Compared with traditional discrete-time (DT)Σ-Δ modulators,CT counterparts achieve high bandwidth,low power and a considerable potential with lower power supply.A singleloop feed-forward third-order CTΣ-Δmodulator with an internal 4-bit quantizer is designed with the standard 0.18μm CMOS process.A compensation for the excess loop delay is implemented in the CTΣ-Δmodulator.It achieves69 dB dynamic range within a 2.2MHz bandwidth,while dissipating only 8.3mW from 1.8Vsupply.