Demonstration circuit 675A is for the evaluation of filter circuits using an LT1568 IC. The LT1568 is a dual second order active-RC filter building block with trimmed internal capacitors and internal low noise op amps with trimmed GBW product. An LT1568 implements high precision and repeatable filter circuits. Using an LT1568, a pair of matched second order lowpass or bandpass filters can be implemented or the two-second order sections may be cascaded to create a fourth order lowpass, bandpass, highpass, notch or allpass filter circuit. The DC675A board contains an LTC1568 with decoupling capacitors, BNC connectors for one or two filter inputs and test pins (turrets) for filter outputs and power supply inputs. The DC675A board is available in four versions configured as follows: The DC675A-A is for general purpose LT1568 filter networks and has uncommitted surface mount pads for 0805 size resistors or capacitors. Printed circuit traces on DC675A-A board configure an LT1568 with the typical connections of external passive components for implementing a dual 2nd or 3rd order or a single 4th or 5th order filter circuit. The DC675A-B is configured as a dual 2nd order, 2.5MHz Butterworth lowpass filter. The DC675A-C is configured as a single 4th order 2.5MHz Elliptic lowpass filter. The DC675A-D is configured as a single 4th order 1MHz bandpass filter.