A low-voltage flexible cascade ΣΔ modulator for beyond-3G wireless telecom

This paper presents a new adaptable cascade SigmaDelta modulator architecture for low-voltage multi-standard applications. It uses two reconfiguration strategies: a programmable global resonation scheme and a variable loop-filter order. These techniques are properly combined in a novel topology that allows to increase the effective resolution in a given bandwidth, whereas keeping relaxed output swing requirements and high robustness to mismatch and to non-linearities of the amplifiers. Time-domain simulations including main circuit-level effects are shown to demonstrate the benefits of the presented modulator when it is configured to cope with the requirements of GSM, UMTS, WLAN and Wi-Max.