These data selectors/multiplexers contain inverters and drivers to supply full on-chip data selection to the four 3-STATE outputs that can interface directly with data lines of bus-organized systems. A 4-bit word selected from one of two sources is routed to the four outputs. The 74AS257 presents true data.
This 3-STATE output feature means that n-bit (paralleled) data selectors with up to 300 sources can be implemented for data buses. It also permits the use of standard TTL registers for data retention throughout the system.
Switching specifications at 50 pF
Switching specifications guaranteed over full temperature and VCC range
Advanced oxide-isolated, ion-implanted Schottky TTL process
Functionally and pin for pin compatible with Schottky, low power Schottky, and advanced low power Schottky TTL counterpart
Improved AC performance over Schottky, low power Schottky, and advanced low power Schottky counterparts
3-STATE buffer-type output drive bus lines directly
Expand any data input point
Multiplex dual data buses
General four functions of two variables (one variable is common)
Source programmable counters
16 pin DIP. Actual brand may vary from picture.