A 6th-Order Active-RC Channel-Select filter with automatic continuous tuning for wideband receivers

Abstract

A sixth-order channel-select filter with automatic continuous tuning for wideband receivers is presented. To reduce the power consumption and improve the bandwidth of the filter a new structure to implement active-RC biquadratic cells has been proposed. Continuous frequency tuning of the filter is also carried out by a new tuning strategy. The layout of the presented 6th-order filter with tuning circuits, occupy 0.372 mm2 of die area. Post-layout simulations have been conducted in a standard 0.18 µm CMOS process and the results show that the filter achieves 60 MHz bandwidth. Moreover, the in-band integrated input referred noise is 175 µVrms and the filter achieves an IIP3 of 12.7 dBm while consuming 5.9 mA from a 1.5-V supply. The simulation results also prove that the automatic tuning technique is quite effective and the deviation of the cut-off frequency due to PVT variations is reduced by almost 43%.