The MC10H115 is a quad differential amplifier designed for use in sensing differential signals over long lines. This 10H part is a functional/ pinout duplication of the standard MECL 10K family part, with 100% improvement in counting frequency and no increase in powersupply current. The base bias supply (VBB) is made available at Pin 9 to make the device useful as a Schmitt trigger, or in other applications where a stable reference voltage is necessary. Active current sources provide the MC10H115 with excellent common mode rejection. If any amplifier in a package is not used, one input of that amplifier must be connected to VBB (Pin 9) to prevent upsetting the current source bias network.