A study about effects of transistors´ nonideal characteristics on log domain filters

In this paper, nonideal effects of transistors on log domain filters are investigated. First order class A log domain filter is synthesized as an example. The state space synthesis method is used for design procedure. Transistors are modeled for finite current gain by using dependent current sources. Each ideal transistor is replaced with modeled ones which have finite current gain. The effects of finite current gain of each transistor are obtained as an extra term in the state space equations. Then, these extra terms are superposed in order to obtain the effects of all transistors which have finite current gain. In order to verify the validity of the offered method, the results obtained from MATLAB and the simulation results obtained from PSpice are compared.