Improved linearity CMOS active resistor structure

Abstract

Original low-power low-voltage active resistor structure with improved performances will be presented. The linearity is strongly increased by implementing an original technique, using a proper current biasing of the differential core. The structures are implemented in 0.35μm CMOS technology and are supplied at ±3V. The circuits present a very good linearity (in the worst case, THD <;0.4%), correlated with an extended range of the input voltage (at least ±0.5V). The tuning range of the active resistors is about hundreds KΩ - MΩ.