An improved nonlinear macromodel of OTA

A new nonlinear macromodel for operational transconductance amplifier (OTA) is presented. It is developed by the 'build-up' technique. Typical parameters, such as differential and common mode input impedance, CMRR, slew rate, and the bias current effect, are taken into account. Model parameters can be calculated from the data sheets supplied by the manufacturers or chosen arbitrarily by the user. The main improvement of the model is that the authors introduce a nonlinear VCCS expressed by a polynomial to simulate the saturation characteristics, so that the nonlinear macromodel is very suitable for SPICE simulation. The results of simulations have proved the adequacy of the macromodel.<>