A 10.7-MHZ 68-DB SNR CMOS CONTINUOUS-TIME FILTER WITH ON-CHIP AUTOMATIC TUNING

A maximally flat 10.7-MHz fourth-order bandpass filter with on-chip automatic tuning system is presented. The signal-to-in-band integrated noise ratio (SNR) of the automatically tuned filter is around 68 dB. The third intermodulation distortion (IM3) is lower than -40 dB for a two-tone input signal of 3.2 V peak to peak (V(p-p)). The complete system operates with supply voltages of +/-2.5 V. The power consumption of the system is 220 mW. All this has been achieved due to the use of a low-distortion transconductor, the development of a high-frequency CMOS resistor, and the realization of an advanced on-chip automatic tuning system for both frequency and bandwidth control. The chip has been fabricated in a standard 1.5-mum n-well CMOS process.