The DC651A demo circuit board is intended to demonstrate the capabilities of the LT?5522 high-signal-level downconverting mixer IC for cable and CATV infrastructure applications. The LT?5522 (Figure 1) is a broadband high signal level active mixer optimized for high linearity downconverter applications including cable (CATV) and wireless infrastructure. The IC includes a high-speed differential LO buffer amplifier driving a double-balanced mixer. The LO buffer is internally 50ohm-matched for wideband, single-ended operation with no external components. The LT5522 IC’s RF input port incorporates an integrated transformer and is internally matched to 50ohms over the 1.2GHz to 2.3GHz frequency range. The RF input match can be shifted down to 600MHz, or up to 2.7GHz, with a single shunt capacitor or inductor, respectively. The high level of integration minimizes the total solution cost, board space and system-level variation. The LT5522 delivers high performance and small size without excessive power consumption. The DC651A demo board allows evaluation of the LT5522 downconverting mixer IC for cable infrastructure applications. Its RF input is optimized for 1150MHz. The IF output frequency range spans 50MHz to 1050MHz. The corresponding range of LO frequencies is 1200MHz to 2200MHz.