DESCRIPTION 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 imple-ments high precision and repeatable filter circuits. Using an LT1568, a pair of matched second order 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 con-tains 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 con-figured as follows: The DC675A-A is for general purpose LT1568 filter networks and has uncommifor 0805 size resistors or capacitors. Printed circuit traces on DC675A-A board configure an LT1568 with the typical connections of external passive featured examples are dual supply circuits and can be converted to single supply circuits by the shunt positions of JP1, JP2 and JP3 (see Figures 1 or 2). In addition, a DC675A-A assembly can implement LT1568 circuits not included in the seven examples. Second order allpass and notch filters and fourth order bandpass filters without external resistors are implemented with a DC675A-A assembly using the RFF1 resistor to design feed-forward circuits. Contact LTC Applications for assistance. QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 675 ACTIVE RC, FILTER BUILDING BLOCK(200KHZ TO 10MHZ) 6 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 675 ACTIVE RC, FILTER BUILDING BLOCK(200KHZ TO 10MHZ) 7 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 675 ACTIVE RC, FILTER BUILDING BLOCK(200KHZ TO 10MHZ) 8 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 675 ACTIVE RC, FILTER BUILDING BLOCK(200KHZ TO 10MHZ) 9 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 675 ACTIVE RC, FILTER BUILDING BLOCK(200KHZ TO 10MHZ) 10 QUICK QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 67