Adaptive SMASH ΣΔ converters for the next generation of mobile phones — Design issues and practical solutions

This paper discusses practical design issues associated to the implementation of ΣΔ analog-to-digital converters intended for mobile telecom applications. After a comprehensive description of the proposed adaptive resonation-based Sturdy MASH ΣΔ modulator, architectural and circuit-level timing limitations are analysed in detail, showing different design trade-offs. As a result of this analysis, a novel time-saving implementation of the dynamic element matching required in the multi-bit front-end digital-to-analog converter is presented. The circuit solutions found can be applied to SC reconfigurable implementations operating up to 320-MHz sampling frequencies. In order to demonstrate the capabilities of the considered modulator, a case study covering a number of standards, including GSM, Bluetooth, UMTS, DVB-H, WiMax and WLAN is shown. Time-domain behavioural simulations including main circuit-level errors validate the presented study.