Improved Linearity Active Resistor with Controllable Negative Resistance

Abstract

An original active resistor circuit is further presented. The main advantages of the new proposed implementations are the improved linearity, the small area consumption and the improved frequency response. An original technique for linearizing the I(V) characteristic of the active resistor will be proposed, based on the utilization of a new linear differential amplifier and on a current-pass circuit. The errors introduced by the second-order effects will be strongly reduced, while the circuit frequency response of the circuit is very good as a result of operating all MOS transistors in the saturation region. In order to design a circuit having a negative equivalent resistance, an original method specific to the proposed implementation of the active resistor circuit will be presented. The circuit is implemented in 035mum CMOS technology, the SPICE simulation confirming the theoretical estimated results and showing a linearity error less than 0.5 % for an extended input range (plusmn500mV) and a small value of the supply voltage (plusmn3.3V)