Transceiver Logic IC; Logic Family:LS; Supply Voltage Min:4.75V; Supply Voltage Max:5.25V; Package/Case:20-SOIC; No. of Pins:20; Operating Temperature Range:0°C to +70°C; Input Type:TTL; Leaded Process Compatible:Yes ;RoHS Compliant: Yes
These octal bus transceivers are designed for asynchronous two-way communication between data buses. The devices transmit data from the A bus to the B bus or from the B bus to the A bus depending upon the level at the direction control (DIR) input. The enable input (G\) can be used to disable the device so the buses are effectively isolated. The -1 versions of the SN74LS640 thru SN74LS642, SN74LS644, and SN74LS645 are identical to the standard versions except that the recommended maximum IOL is increased to 48 milliamperes. There are no -1 versions of the SN54LS640 thru SN54LS642, SN54LS644, and SN54LS645. The SN54LS640 thru SN54LS642, SN54LS644, and SN54LS645 are characterized for operation over the full military temperature range of -55C to 125C. The SN74LS640 thru SN74LS642, SN74LS644, and SN74LS645 are characterized for operation from 0C to 70C.