Improved Linearity Active Resistor Using Equivalent FGMOS Devices

An original active resistor circuit was presented in this paper. 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 was proposed, based on a parallel connection of two quasi-identical circuits opposite excited and different polarized having the result of improving the circuit linearity with about an order of magnitude. The errors introduced by the second-order effects were also strongly reduced, while the advantage of using FGMOS devices is achieved maintaining the compatibility with classical technologies. The frequency response of the circuit is very good as a result of operating all MOS transistors in the saturation region. The circuit is implemented in 0.35mum CMOS technology, the SPICE simulation confirming the theoretical estimated results and showing a linearity error under a percent for an extended input range (plusmn500mV) and a small value of the supply voltage (plusmn3V)