Integrated Continuous-Time Balanced Filters for 16-Bit DSP Interfaces

A fully-balanced integrated continuous-time leapfrog filter, with signal linearity and dynamic range compatible with 16-bit digital audio processing, is presented. The filter employs high performance balanced op-amps and linear resistors; switchable arrays of linear capacitors controlled by a digital code perform the response tuning function. A new area efficient automatic on-chip calibrator capable of programming the response of the leapfrog filter is described. All circuitry was fabricated in a standard CMOS process. -94dB THD and dynamic range of 95dB are achieved with a 5V supply.