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.
   
• Propagation Delay, 1.5 ns Typical
• Power Dissipation, 197 mW Typical
• Improved Noise Margin 150 mV (Over Operating Voltage and
    Temperature Range)
• Voltage Compensated
• MECL 10K–Compatible