Fully integrated analog filters using bipolar-JFET technology [active fifth order Chebyshev low-pass realisation]

A new approach for realizing high-order analog filters which can be fully integrated using a compatible bipolar and ion-implanted JFET process is described. This approach is based on the recognition that what is really needed is a long time constant monolithic integrator which can be effectively realized in a small silicon area. These integrators have been designed, fabricated, and used in a `leapfrog' or active ladder configuration to realize a fifth-order 8 kHz Chebyshev low-pass filter with 0.1 dB passband ripple. No external trimming operations and no anti-aliasing prefilter are required.