Noise optimization in operational transconductance amplifier filters

The noise performances of a class of biquadratic time-continuous filters based on the use of operational transconductance amplifiers and capacitors (OTA-C filters) are investigated and compared in terms of the filter parameters and topologies. Both white and 1/f noise are included in modeling the noise characteristics of a real OTA, and expressions for the total output noise are given for biquadratic sections. Indications for the best choice of the capacitor values and transconductance gains are given, in order to minimize the total output noise. The use of a circuit optimizer like NICE-SPICE for the direct optimization of the dynamic range has been investigated.<>