Conditions for the existence and uniqueness of DC solutions of networks containing nonlinear OpAmps with ideal model

The authors give necessary and sufficient conditions for the existence and uniqueness of DC solutions of resistive networks containing nonlinear operational amplifiers with an ideal model. Sandberg, Willson and other authors, studying similar problems for devices with a non-ideal model, have proved the importance of two classes of matrices called class P_o and class P . Conditions are given in terms of these classes of matrices