A11083 - DM74S257N 3-State Quad Data Selector/Multiplexer (National)

These Schottky-clamped high-performance multiplexers feature 3-state outputs that can interface directly with data lines of bus-organized systems. With all but one of the common outputs disabled (at a high impedance state), the low impedance of the single enabled output will drive the bus line to a HIGH or LOW logic level. To minimize the possibility that two outputs will attempt to take a common bus to opposite logic levels, the output enable circuitry is designed such that the output disable times are shorter than the output enable times. This 3-state output feature means that n-bit (paralleled) data selectors with up to 258 sources can be implemented for data buses. It also permits the use of standard TTL registers for data retention throughout the system.

Features:
Schottky-clamped for significant improvement in A-C performance
Provides bus interface from multiple sources in high-performance systems
Average propagation delay from data input 4.8 ns
Typical power dissipation

16 pin DIP. Manufactured with National.
A11083