Design Considerations for Multistandard Cascade Σ∆ Modulators

This paper discusses design considerations for cascade Sigma-Delta Modulators (Σ∆Ms) included in multistandard wireless receivers. Four different standards are covered: GSM, Bluetooth, UMTS, and WLAN. A top-down design methodology is proposed to find out the optimum modulator architecture in terms of circuit complexity and reconfiguration parameters. Several reconfiguration strategies are adopted at both architectureand circuit-level in order to adapt the modulator performance to the different standards requirements with adaptive power consumption. Time-domain behavioural simulations considering a 0.13μm CMOS implementation are shown to validate the presented approach.†