A low-power 10MHz bandwidth continuous-time ΣΔ ADC with Gm-C filter

In this paper, we design a high-speed and wide-bandwidth continuous-time sigma-delta modulator (CT-SDM). We emphasize the design of low power wide-bandwidth (10MHz) CT-SDM for WLAN Std. 802.11b receiver. In the application of wireless receiver, continuous-time sigma-delta ADC is more suitable than pipeline ADC. Instead of active-RC filter, we use Gm-C filter in our CT-SDM design because Gm-C filter consumes lower power and requires less limitation on op-amp. The CT-SDM is implemented with TSMC 0.35μm CMOS process. The proposed CT-SDM achieves a 43dB peak SNR and 48-db DR with a 10-MHz bandwidth at a 1GHz sampling rate for WLAN Std. 802.11b. The power consumption is 17.3mW with 3.3V power supply.