Abstract: A new Q-enhanced SC second order lowpass filter is presented.The circuit is derived from the Sallen-Key's active RC circuit with a unity-gain amplifier. The optimal design of the minimun capacitor spread for the circuits proposed.Pole ω₀ and pole Q sensitivities as well as gain-bandwidth product effects of the SC circuit are also investigated.Computation shows that the capacitor spread for the proposed circuit can be significantly reduced.The validity for the circuit is verified by the experiment with discrete elements.

Key words: switched -capacitor, lowpass filter