Reconfigurable ADCs enable smart radios for 4G wireless connectivity

A reconfigurable ADC based on a 2-2 modified cascaded SigmaDelta modulator designed for a GSM/WCDMA/WLAN/WiMAX zero-IF receiver has been presented. Employing the second-order feedforward SigmaDelta modulator in a 2-2 modified cascaded configuration, a high linearity over 100 kHz/2 MHz/10 MHz signal bandwidth is achieved. The P-DWA technique is applied in the first feedback 4-b DAC to eliminate the spurious tones associated with the multibit DAC nonlinearity in the WLAN/WiMAX modes