A single-chip NMOS analog front-end LSI for modems

Abstract

Presents a fully integrated analog front-end LSI chip which is an interface system between digital signal processors and existing analog telecommunication networks. The developed analog LSI chip includes many high level function blocks such as A/D and D/A converters with 11 bit resolution, various kinds of SCFs, an AGC circuit, an external control level adjuster, a carrier detector, and a zero crossing detector. Design techniques employed are mainly directed toward circuit size reductions. The LSI chip is fabricated in a 5 /spl mu/m line double polysilicon gate NMOS process. Chip size is 7.14/spl times/6.51 mm. The circuit operates on /spl plusmn/5 V power supplies. Typical power consumption is 270 mW. By using this analog front-end LSI chip and a digital signal processor, modern systems can be successfully constructed in a compact size.