Pseudo-exponential function for MOSFETs in saturation

In this paper, according to the Taylor's series expansion, two pseudo-exponential circuits were realized. The proposed circuits provide a simple method to synthesize pseudo-exponential circuits. Both of the circuits were composed of MOS transistors operating in saturation. One of the pseudo-exponential function circuits is voltage-mode and was tested using discrete components. The other one is current-mode, which is verified with the 0.8 /spl mu/m CMOS process by Hspice simulations. The results confirm the feasibility of the proposed circuits.