Low-voltage CMOS cross-quad implementation based on dynamic positive feedback

This paper presents the implementation of a cross-quad circuit suitable for low-voltage operation. The proposed cell exploits a dynamic positive feedback g_m boosting technique to achieve linear voltage-to-current conversion, while it manages to work with low-voltage with no extra bias current and minimal additional hardware. Results for a 0.5 mum CMOS implementation supplied at 3 V show a 0.972% voltage-to-current accuracy, improving the 0.867% accuracy of a previously reported cross-quad topology also suitable for low-voltage operation which is based on folded transistors.