Peter Pessl

A 85-dB dynamic range multibit delta-sigma ADC for ADSL-CO applications in 0.18-/spl mu/m CMOS

A high-resolution multibit sigma-delta analog-to-digital converter (ADC) implemented in a 0.18-/spl mu/m CMOS technology is introduced. The circuit is targeted for an asymmetrical digital subscriber line (ADSL) central-office (CO) application . An area- and power-efficient realization of a second-order single-loop 3-bit modulator with an oversampling ratio of 96 is presented. The /spl Sigma//spl Delta/ modulator features an 85-dB dynamic range over a 300-kHz signal bandwidth. The measured power consumption of the ADC core is only 15 mW. An innovative biasing circuitry is introduced for the switched-capacitor integrators.

Low-power 14-bit current steering DAC, for ADSL2+/CO applications in 0.13/spl mu/m CMOS

This work presents a 6-bit fully-differential current steering digital-to-analog converter (DAC), oversampled and 2/sup nd/ order noiseshaped. It is implemented in a 0.13 /spl mu/m standard CMOS process, using only regular threshold voltage devices. The circuit is targeted at ADSL2+ central-office (CO) applications. Clocked at 105 MHz from a low-jitter PLL, it yields a multi-tone power ratio (MTPR) higher than 75 dBc for DMT signals, with an output swing of 1.4 V peak-to-peak. It has an effective resolution of more than 14.5 ENOBs (effective number of bits), consuming only 9 mW from a single 1.5 V supply.

A four-channel ADSL2+ analog front-end for CO applications with 75 mW per channel, built in 0.13-/spl mu/m CMOS

This paper describes a four-channel ADSL2+ analog front-end (AFE) targeted at a central office application, with a power consumption of 75 mW per channel. The design is implemented using a modern 0.13-/spl mu/m CMOS process. The AFE consists of a 14-bit ADC and DAC, a very low-noise high-linearity automatic gain control (AGC), analog filter blocks, and digital decimation and interpolation filter stages. The design has been optimized to achieve the lowest possible power consumption, high performance, and cost efficiency.