74LS245/54LS245 pdf datasheet

54LS245/DM54LS245/DM74LS245
TRI-STATEÉ Octal Bus Transceiver
General Description
These octal bus transceivers are designed for asynchronous
two-way communication between data buses. The
control function implementation minimizes external timing
requirements.
The device allows data transmission from the A bus to the B
bus or from the B bus to the A bus depending upon the logic
level at the direction control (DIR) input. The enable input
(G) can be used to disable the device so that the buses are
effectively isolated.
Features
Y Bi-Directional bus transceiver in a high-density 20-pin
package
Y TRI-STATE outputs drive bus lines directly
Y PNP inputs reduce DC loading on bus lines
Y Hysteresis at bus inputs improve noise margins
Y Typical propagation delay times, port-to-port 8 ns
Y Typical enable/disable times 17 ns
Y IOL (sink current)
54LS 12 mA
74LS 24 mA
Y IOH (source current)
54LS b12 mA
74LS b15 mA
Y Alternate Military/Aerospace device (54LS245) is available.
Contact a National Semiconductor Sales Office/
Distributor for specifications.