The MC10H158 is a quad two channel multiplexer with common input select. A "high" level select enables input D00 D10 D20 and D30 and a "low" level select enables input D01 D11 D21 and D31. This MECL 10H part is a functional/pinout duplication of the standard MECL 10K family part with 100% improvement in propagation delay and no increase in power-supply current.