A 65-dB DR 1-MHz BW 110-MHz IF bandpass ΣΔ modulator employing electromechanical loop filter

A 4^th-order bandpass ΣΔ modulator employing electromechanical filter as loop filter is proposed. The electromechanical loop filter has the advantages of low power consumption and accurate center frequency without the need for tuning. The proposed bandpass SigmaDelta modulator is implemented in a 0.35-μm SiGe BiCMOS technology and tested with a 110-MHz SAW filter. When sampled at 440 MHz, the prototype chip achieves 65-dB DR and 60-dB peak SNDR in a 1-MHz signal bandwidth.