SN75107AN (TEXAS INSTRUMENTS)

The SN75107AN is a dual TTL-compatible high-speed Line Receiver feature two independent channels. It is designed for general use, as well as for such specific applications as data comparators and balanced, unbalanced and party-line transmission systems. The essential difference between the A and B versions can be seen in the schematics. Input-protection diodes are in series with the collectors of the differential-input transistors of the B versions. These diodes are useful in certain party-line systems that have multiple VCC+ power supplies and can be operated with some of the VCC+ supplies turned off. In such a system, if a supply is turned off and allowed to go to ground, the equivalent input circuit connected to that supply would be as follows. This would be a problem in specific systems that might have the transmission lines biased to some potential greater than 1.4V.