A fully differential CMOS OTA for continuous-time filter applications

A CMOS operational transconductance amplifier (OTA) operating from single 3.3 V power supply is desirable for continuous-time filter applications. The developed OTA has been used in 100 kHz fifth-order, elliptic filter based on RLC ladder prototype. Input stage of OTA works as degenerated MOS differential pair with new concept of active MOS resistance. PSPICE (models BSIM3v3) simulations and measurements results of test chip (fabricated in 0.8 /spl mu/m CMOS process - AMS) are presented. The results demonstrate that the OTA-C filter exhibits dynamic range equal to 55 dB at power consumption of 3.9 mW.