Demonstration circuit 962 features the LT6600-XX series of a fully differential4th order lowpass filter approximating a Chebyshev frequency response. The cutoff frequencies (Fc) ofLT6600-XX are:2.5MHz, 5MHz, 10MHz, 15MHz and 20MHz (see Table 1).The LT6600-XX combines a lowpass filter with a fully differential amplifier for driving the differential input of an analog to Digital Converter (ADC). An LT6600-XX also provides the necessary level shifting to set its output common mode voltage to accommodate the reference voltage requirements of an ADC. An LT6600-XX filter IC requires only two external input resistors to set the filter’s differential gain. A DC962 board contains an LT6600-XX lowpass filter configured with input resistors as a unity gain differential amplifier. Gains greater than one require changing the input resistors to a lower value (refer to DC962 schematic). Connection to the differential input and output of a DC962 is through SMA connectors. On board jumpers configure the DC962 for dual or single supply operation. The differential input of a DC962 is AC coupled and can be configured for DC coupling by shorting the input capacitors with zero ohms surface-mount resistor jumpers. In addition, the DC962 has surface-mount pads to add input passive components for input signal filtering and DC biasing.