Custom IC design for cellular terminals

This paper reviews the basic functional building blocks and performance requirements of EIA/IS-3 and UK/TACS cellular communications terminals. Cost/performance justifications for utilizing custom VLSI in designing transceivers are illustrated using NovAtel's new 800/900 MHz product family as a case study. The overall goal was to integrate those components which would afford the greatest reduction in cost, component count, physical size and power consumption, while maintaining or improving the high performance of earlier products. Major design trade-offs are presented that occurred during the development of two generic CMOS devices - an analog switched capacitor filter chip and a digital data transmission subsystem chip. The analog chip performs well over 90% of the filtering of both audio and data signals on the transmit and receive side. The digital chip performs most of the functions required to recover and transmit the 10 Kbps or 8 Kbps data control signal. Both chips can be configured for either 800 MHz (EIA/IS-3) or 900 MHz (UK/TACS) application.