Current-mode temperature compensated continuous-time CMOS transconductance-C filter

In this paper a low voltage low power current-mode continuous-time low-pass filter is presented. The current-integrator is constructed of a multi-output linearized transconductance element driven by a balanced transimpedance amplifier. A 1 MHz third order elliptic low pass filter is designed and fabricated with the proposed current-mode integrator. The measurements show capability of operation with down to a 3 V supply voltage. The measured current consumption is 850 mu A at room temperature and the dynamic range is 66 dB. The distortion of the filter is below 50 dBc with peak signal levels up to twice the quiescent current level and with the refined designs even lower distortion is expected. The filter uses a CMOS-current reference for temperature and process variation stabilization with a measured corner frequency temperature coefficient of -100 ppm/K.