Cascode circuits for low-voltage and low-current applications

Different cascode circuits are investigated with regard to their suitability for low-voltage and low-current circuits. A generalized circuit representation is introduced and different cascode circuits are discussed with respect to their small-signal parameters as well as their associated dynamic output ranges. The output voltage ranges for saturation operation of the different cascode circuits are derived and the saturation operating areas are compared. A method called reference voltage and current tracking for dynamic output range improvement of cascode circuits with reference voltage or current is described. An improved regulated cascode circuit with extended dynamic output range using input tracking and level shifting technique is proposed.