A maximally flat magnitude 70 MHz fourth-order bandpass filter with an on-chip automatic tuning system is presented. The input equivalent noise is 19 μV/sqr(Hz) which shows that the nonlinearity at the input of the filter is very small. The IIP3 (the input level of the third-order intercept point) of the filter is -9.25dBm. The complete system operates with a supply voltage of 2.2 V. All this has been achieved due to the use of a low distortion transconductor, and the realization of an advanced on-chip automatic tuning system for both frequency and bandwidth control. The whole circuit has been implemented in 0.35 μm CMOS technology available through the Canadian Microelectronics Corporation (CMC).