Digitally Tunable Section for an Analog Current-Mode Predistortion

The paper describes a circuit system which is able to process an analog current mode signals. It is intended to use it as a preamplifier and corrector of the transfer characteristic of some kind of sensor. The circuit is based on the sub-threshold CMOS multiplying cells. Those cells are interconnected by the current mirrors to form a circuit with desired transfer characteristic. There are two ways how to use this circuit. It can be used for direct linearization (pre-distortion) of the signal from the sensor or it can be encircled by a negative feedback in order to realize the inverse function. The circuit is dedicated for slow signals and for extremely low power applications. The transfer characteristic is tunable aid four ten-bit digital to analog converters. The program CADENCE and the CMOS 180 nm technology were used for simulations.