New ELIN Systems Using CMOS Transistors in Weak Inversion Operation

In this paper new ELIN systems implemented by using CMOS transistors in weak inversion operation are presented. The proposed systems exploit the exponential-law characteristics of the subthreshold CMOS transistors. New operational transconductance amplifiers in CMOS technology, providing elementary "tanh" and "sinh/cosh" functions with high accuracy are proposed. These elementary cells are used to design first order CMOS ELIN filters. For a bias current of 1 mu A, the dynamic range of the predistorted input voltage is 220mV(pp) and the current consumption is about 20 mu A from a 3.3V supply voltage. The simulations performed in 0.18 mu m CMOS technology confirm the theoretically obtained results.