Wide Band Linear Voltage-to-Current Converter Design

In this work, we propose a wide band linear voltage-to-current converter (VIC) with mobility degradation compensation. By use of NMOS output stage and grounding NMOS input stage, PSRR enhances as well as body effect decreases. In addition, through utilizing the sum of two current sources operate in linear and saturation region respectively, the nonlinearity of complementary parabolic voltage to current characteristics caused by mobility degradation are reduced. A feedback loop is then inserted to increase bandwidth, so that the proposed VIC is useful in further applications. A practical chip was fabricated by TSMC 0.35 3.3V CMOS process with its measured transconductance, bandwidth, and operational range are 0.975~1.032, 85.5MHz, and 1.2V respectively. The experiment results show that the proposed design significantly improves bandwidth and the nonlinearity effect of VIC originated from mobility degradation.