A 160-kb/s digital subscriber loop transceiver with memory compensation echo canceller

A full-duplex transceiver chip incorporating an adaptive echo cancelling modem and a 2.048-Mb/s serial interface is described. The device provides a full-duplex communication link at 160 or 80 kb/s on up to 4 or 5 km, respectively, of 0.5-mm twisted-pair cable. Full integration is achieved through the use of RAM-based sign-algorithm echo-cancellation, biphase line code, a fixed switched-capacitor equalizer and a digital phase locked loop. The paper emphasizes system design considerations and a chip architecture minimizing power dissipation, silicon area and off-chip components. A double poly 3-mum CMOS technology is used to implement the 5-V 22-pin device which dissipates less that 50 mW and occupies 27.7mm^2.