A low-voltage low-power complex active-RC filter employing single-stage opamp

A low-voltage low-power complex channel select filter for low-IF transceiver employing unbuffered single-stage opamp is described. The opamp imperfections have been compensated with a simple technique that is suitable for low-voltage low-power applications. A 1-MHz center frequency fifth-order Chebyshev complex filter has been designed in a standard 0.18-μm CMOS process with 1 MHz bandwidth and 0.5-dB equiripple passband response for Bluetooth application. Simulation results show that it consumes only about 1 mW and achieves out-of-band third-order input intercept point (IIP3) of 37.5 dBV_p at 1-V single supply.