The MAX3841 is a low-power, 12.5Gbps 2 x 2 crosspoint switch IC for high-speed serial data loopback, redundancy, and switching applications. The MAX3841 current-mode logic (CML) inputs and outputs have isolated VCC connections to enable DC-coupled interfaces to 1.8V, 2.5V, or 3.3V CML ICs. Fully differential signal paths and Maxim's second-generation SiGe technology provide optimum signal integrity, minimizing jitter, crosstalk, and signal skew. The MAX3841 is ideal for serial OC-192 and 10GbE optical module, line card, switch fabric, and similar applications. The MAX3841 has 150mVP-P minimum differential input sensitivity, and 500mVP-P nominal differential output swing. Unused outputs can be powered down individually to conserve power. In addition to functioning as a 2 x 2 switch, the MAX3841 can be configured as a 2:1 multiplexer, 1:2 buffer, or dual 1:1 buffer. The MAX3841 is available in a 4mm x 4mm 24-pin thin QFN package, and consumes only 215mW with both outputs enabled.