A widely tunable continuous-time LPF for a direct conversion DBS Tuner

Bei Chen, Fangxiong Chen, Heping Ma, Yin Shi, Fa Foster Dai
2008 2008 9th International Conference on Solid-State and Integrated-Circuit Technology  
A continuous-time 7th-order Butterworth Gm-C low pass filter (LPF) with on-chip automatic tuning circuit has been implemented for a direct conversion DBS tuner in 0.35 µm SiGe BiCMOS technology. The filter's −3 dB cutoff frequency f 0 can be tuned from 4 to 40 MHz. A novel on-chip automatic tuning scheme has been successfully realized to tune and lock the filter's cutoff frequency. Measurement results show that the filter has −0.5 dB passband gain, +/-5% bandwidth accuracy, 30 nV/Hz 1/2 input
more » ... 0 nV/Hz 1/2 input referred noise, −3 dBVrms passband IIP3, and 27 dBVrms stopband IIP3. The I/Q LPFs with the tuning circuit draw 13 mA (with f 0 = 20 MHz) from 5 V supply, and occupy 0.5 mm 2 .
doi:10.1109/icsict.2008.4734889 fatcat:scvvo47bl5h5rl4eh4v3ps7uwu