Exact design of arbitrary parasitic-insensitive elliptic SC-ladder filters in the z-domain

A novel exact design procedure for arbitrary elliptic switched-capacitor (SC) ladder filters (including highpass filters) is presented. Starting with the z-domain transfer function, the procedure calculates the chain parameters of a doubly terminated reactance two-port, from which it derives a discrete-time R-LC filter prototype with simple terminations of the form z^1/2 or z^-1/2. With the use of this discrete-time prototype, simple and insensitive SC ladder realizations can be obtained without any additional amplifiers. Using this design technique in an automated SC filter generator, numerous filters have been designed and fabricated as CMOS chips with excellent results