The MAX9401/MAX9404 are extremely fast and lowskew quad ECL/PECL differential buffers/receivers for data and clock signals. The four channels can be operated synchronously with an external clock, or in asynchronous mode, determined by the state of the SEL input. An enable input provides the ability to force all the outputs to a differential low state. The MAX9401 has high-impedance (open) input and the MAX9404 has an integrated 100 differential input termination, which reduces external component count. Both devices have double amplitude swing open emitter outputs suitable for driving long cables. The MAX9401/MAX9404 operate over a VCC - VEE = +3.0V to +5.5V supply range, and are specified for operation from -40C to +85C. These devices are offered in space-saving 32-pin 5mm x 5mm QFN exposed-paddle (EP) and TQFP packages.