A tunable floating gate CMOS resistor for low-power and low-voltage applications

This paper describes an implementation of a tunable CMOS resistor that can be fully integrated in a standard CMOS technology with low-power and low-voltage applications. It is built by exploiting the capacitive coupling and voltage storage capabilities of a floating-gate transistor. Also, a scaled-gate linearization technique is utilized to suppress the transistor nonlinearities in the triode region. The resistance of the proposed circuit is tuned by utilizing Fowler-Nordheim tunnelling and hot-electron injection quantum mechanical phenomena. We present experimental data from the chip that was fabricated in 0.5mum CMOS process, and show that this resistor exhibits total harmonic distortion (THD) better than 7-bit linearity for 1KHz 1V_pp sinusoidal input