80 MHz bandpass delta-sigma modulator using switched-capacitor resonator structure

A fully differential 80 MHz fourth-order bandpass /spl Delta//spl Sigma/ modulator, meant for a 100 MHz GSM/WCDMA multimode IF receiver, is presented. The modulator is based on a double-delay single opamp SC-resonator structure which is well suited for low supply voltages. Furthermore, the centre frequency of the topology is insensitive to different component variances. The measured peak SNR is 78 dB and 43.3 dB for 270 kHz (GSM) and 3.84 MHz (WCDMA) bandwidths, respectively.

[1]  K. Halonen,et al.  2.7 V 50 MHz IF sampling /spl Delta//spl Sigma/ modulator with +37 dBV IIP3 , 2001 .

[2]  W. Liu,et al.  A neuro-stimulus chip with telemetry unit for retinal prosthetic device , 2000, IEEE Journal of Solid-State Circuits.

[3]  A. Hairapetian,et al.  An 81 MHz IF receiver in CMOS , 1996, 1996 IEEE International Solid-State Circuits Conference. Digest of TEchnical Papers, ISSCC.

[4]  Shen-Iuan Liu,et al.  A double-sampling pseudo-two-path bandpass /spl Delta//spl Sigma/ modulator , 2000, IEEE Journal of Solid-State Circuits.