On the design of low-frequency filters using CMOS OTAs operating in the subthreshold region
Design considerations on a circuit technique based on subthreshold operation of MOS transistors is described for the realization of low-frequency OTA-C active filters with small capacitance values of the order of 25400pF. The circuit technique described is applied to the ? (812Hz), ? (1340Hz), ? (48Hz) and ? (14Hz) band filters for EEG signals. Because of small capacitance values the filter circuit is suitable for realization on a single VLSI chip using the CMOS technology, and enables the user to implement the circuit on implantable biotelemetric applications.
filter cmos ota subthreshold region low power