A CMOS ANALOG FRONT-END CIRCUIT FOR AN FDM-BASED ADSL SYSTEM

A CMOS analog front-end circuit for an FDM-hased ADSL system is presen ted, The circuit contains all analog functions including AGC amplifier s, continuous-time band pass filters, Sigma Delta AD/DA converters, an d digital decimation and interpolation filters, On-chip automatic tuni ng of the bandpass filters provides more than 300% center frequency ra nge with 1% frequency accuracy, The higher-order Sigma Delta AD/DA con verters achieve 12-b data conversion at 1.54 Msamples/s with an oversa mpling ratio of only 32, The 0.7 mu m CMOS circuit measures 65 mm(2) a nd consumes 1.9 W from a single 5 V power supply.