A fifth-order elliptic low-pass Gm-C filter used in monolithic DAB receiver is presented, the filter integrates an on-chip frequency automatic tuning circuit based on PLL to control the cutoff frequency. The filter has been implemented in 0.25muum CMOS process. The measurement results show that the frequency tuning error is within 1%, the dynamic range is 54dB, the stop-band rejection rate is greater than 40dB. The filter draws 13mA current from a 3.3V power supply