A switched-capacitor filter in 2 /spl mu/m CMOS using parallelism to sample at 80 MHz

Switched-capacitor filters (SCFs) are usually used in low-frequency applications, where the ratio of sample rate to corner frequency is high enough so that only simple anti-alias filters are required. At video bandwidths in CMOS technologies, however, op-amp settling time limits this ratio and increases the complexity of the anti-alias filter. Op amps and anti-aliasing are not needed with a continuous-time, transconductance-capacitor structure, but, this approach requires complex tuning. To avoid such tuning and to increase the sample-rate-to-corner-frequency ratio, this paper describes a prototype SCF that uses parallelism.<>