A 4th Order Chebychev Active-RC Low-Pass Filter With 5/10/20/30/40/50 MHz Tunable Bandwidth and Low Power

Based on 40nm CMOS process, a tunable fourth order Chebychev low pass filter design was proposed for analog baseband circuits. The filter consists of two cascaded Tow-Thomas biquads and a clock-controlled series peripheral interface. The Tow-Thomas biquads utilized feedforward-compensated operational amplifiers. Tunable Capacitors and resistors were introduced to adjust the bandwidth. Simulation results show that the filter achieves a bandwidth of 5/10/20/30/40/50MHz with in-band fluctuations no more than 0.4 dB and its input-referred third order intermodulation point is at 15.6 dBm. The power consumption of the whole circuit is less than 5 mW. The filter layout occupies 751$\times 551 \mu m ^{2}$.