A Novel Nauta Transconductor for Ultra-Wideband gm-C Filter with Temperature Calibration

In this paper, a novel modified Nauta OTA has been proposed for achieving temperature independent property. A tuning voltage is applied to the bodies of the differential input PMOS transistors, resulting in the variable threshold voltage of the transistors and then changing the transconductance of the Nauta OTA. And a high precision bandgap reference is used for generating a proportional to absolute temperature (PTAT) voltage to monitor the temperature of the chip. The proposed Nauta transconductor is implemented in TSMC 65-nm standard CMOS process. Simulation results show that the transconductance tunability performs less than 0.1% over the temperature range of -40 degrees C to 120 degrees C. This method is demonstrated that temperature variation has slight influence on the transconductance fluctuation after accurate trimming.