A 0.5 μ CMOS ADSL analog front-end IC

Asymmetrical digital subscriber line (ADSL) provides robust transport of data at up to 8 Mb/s on common twisted pair without interfering with classical telephone service. ADSL uses multicarrier modulation (DMT) to modulate up to 256 QAM into a 1.104 MHz frequency band, which requires a signal path with at least 66 dB of dynamic range for full performance. The circuit described operates either as ATU-C (central office) or as ATU-R (customer premises) ADSL analog front-end by swapping upstream and downstream filters