A Low-Power Reconfigurable Cross-Coupled ΣΔ Modulator for Multi-standard Wireless Applications

A novel low-power reconfigurable time-interleaved (TI) symmetric cross-coupled sigma-delta (ΣΔ) modulator intended for GSM/ Bluetooth/ GPS/ WCDMA/ WLAN /WiMAX multi-standard application has been proposed in this paper. The modulator is based on TI cross-coupled first order ΣΔ paths with enhanced noise shaping characteristics. A new dual-extended (DE) noise shaping technique is introduced in the modulator to achieve power and area efficiency, satisfying desired Quality of Service. The ΣΔ modulator reconfigures its enhanced noise shaping cross-coupled paths and building blocks in order to adapt the performance to the diverse multistandard specifications. The TI cross-coupling technique is adopted as an elegant way to decrease the operating speed or equivalently to increase the conversion bandwidth of ΣΔ modulators. Compared to other alternatives, an improved peak SNR of 93/ 93/ 70/ 67/ 62/ 51 dB is achieved for GSM/ Bluetooth/GPS/WCDMA/WLAN/WiMAX mode with low over-sampling ratio (OSR) and minimum hardware. The simulation results demonstrate the efficiency and feasibility of the proposed modulator and it fulfills the performance requirements of the mobile communication standards mentioned above.