Performant Cmos Active Resistor Based on Improved Linearity Differential Structures

An original active resistor circuit will be presented, having the main advantages of an improved linearity, a small area consumption and a very good frequency response. An original technique for linearizing the ) (V I characteristic of the active resistor will be proposed, based on the utilization of a new linear differential amplifier and on a currentpass circuit. The linearization of the original differential structure will be achieved by implementing an original method of compensating the quadratic characteristic of the MOS transistor working in saturation by two complementary square-root circuits. The errors introduced by the second-order effects will be quantitative evaluated, while the circuit frequency response of the circuit will be very good as a result of biasing all MOS transistors in the saturation region and of a current-mode operation of the square-root circuits. The active resistor is implemented in m 35 0 μ . CMOS technology, the linearity error being under a percent for an extended input range and for a small value of the supply voltage ) ( V 3 ± .