Design of a 15-MHz CMOS continuous-time filter with on-chip tuning

A fifth-order CMOS continuous-time Bessel filter with a tunable 6- to 15-MHz cutoff frequency is described. This fully balanced transconductance-capacitor (G/sub m/-C) leapfrog filter achieves a dynamic range of 55 dB while dissipating 96 mW in a 5-V 0.9- mu m CMOS process. The author reviews the disk drive application and filtering requirements, and explains why the G/sub m/-C continuous-time filtering approach was used. The on-chip master-slave tuning system uses a voltage-controlled oscillator (VCO). Experimental results are presented.<>