A CMOS ADSL codec for central office applications

Abstract

A CMOS central office codec that supports Full Rate and G.Lite ADSL applications is described. The transmit channel consists of application-dependent digital filters, a 14 bit, 8.832 MSample/s current steering DAC, a 1.104 MHz analog filter and a programmable attenuator. The receive channel contains -17.5 to 33.5 dB of programmable gain, a 138 kHz analog low-pass filter, a 14 bit, 2.208 MSample/s pipeline ADC and a digital low-pass filter. The IC occupies 55.2 mm/sup 2/ and dissipates 450 mW from a 3.3 V supply.