Noise performances of OTA-C filters

Noise performances of OTA-C (operational transconductance amplifiers and capacitors) filters are presented in order to derive their dynamic range limitations. In particular, the noise performances of elementary building blocks are considered, and then the noise of several OTA-C biquadratic structures is evaluated. Both white and 1/f noise contributions are taken into account. Analytical expressions and simulated results are given together with some practical design considerations. The results put in evidence how the choice of any topology affects the noise limitations of the filter. Topologies that allow more degrees of freedom correspond to noisier structures.<<ETX>>