Low-power fine-tuning switched-resistor reconfigurable filter

This paper describes a low-power fine-tuning reconfigurable filter using switched-resistor technique, which offers tunability and high linearity at low supply voltage. The internal pole of the opamp has been utilized to implement the filter transfer function so that only one opamp is required to implement a second-order filter. The opamp´s unity-gain-bandwidth is comparable to the filter cut-off frequency, so the power consumption is strongly reduced. Simulation results of a 10-MHz biquad low-pass filter using AMS 0.18-μm CMOS process, operating at 1-V supply, and consuming 180 μW power, are also given.