Switched-capacitor filters that are preset for a given bandwidth sometimes do not deliver the bandwidth or Q an application requires. By inverting the clock between two switched-capacitor bandpass filters, such as the MSFS1 from Mixed Signal Integration Corp, you can configure a high-Q filter (Figure 1). The MSFS1 is a selectable, seventh-order, lowpass/bandpass, switched-capacitor filter. Using the FSEL pin, you can select either a lowpass or a bandpass response. With the TYPE pin, you can select a Butterworth, a Bessel, or an elliptic response if FSEL is low.