Abstract
This paper proposes a highly linear transconductance cell with a widely tunable control voltage based on a bulk-driven technique. The transconductance is configured using a self-biasing structure to achieve high linear operation under control-voltage variations. In addition, the transistors of the input differential pair are driven from the bulk terminal to increase the input dynamic range and provide a low-voltage structure. A reference voltage is embedded to control the transistors' DC currents and balance the circuit's operation under unwanted variations such as corner cases. The proposed cell is simulated via 180-nm CMOS technology under a supply of 0.5 V. The simulation results show that the DC gain changes from 0 dB to 14.2 dB for control-voltage variations in the range of 0–0.5 V. Moreover, the common mode input voltage can change from 0.125 V to 0.375 V without any degeneration in linearity, which results in a 0.25 V input dynamic range. The proposed cell consumes only 250 nW of power, which is suitable for ultralow-power applications.