Design of OTA-C Active Low Pass Filter Using Multiple OTA’s

Abstract

The studies are carried out on OTA-C active filter using single OTA-C and multiple OTA-C filter. The multiple OTA-C filters have the advantage of tuning the floating inductor resulting in enhancement of gain and increase in cutoff frequency with increase in bias current. Different cases of tuning transconductance g m1, g m1, g m , and g m2 by changing the bias currents of multiple OTA 's are studied and results are discussed. The only one method of setting of g m1 g m1 greater than g m g m2 is an innovative in changing the cut off frequency as we have flexible tuning transconductances of g m1, g m1, g m and g m2. Results are consistent and are encouraging in respect of tuning of transconductance with bias current under the condition of g m1 g m1 greater than g m g m2. However an OTA-C active filter other than the studied criteria has the limitations in designing of filters.