These octal bus transceivers are designed for asynchronous two-way communication between data buses. These 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 output-enable (
) input can be used to disable the device so that the buses are effectively isolated.
The -1 version of the SN74ALS640B is identical to the standard version, except that the recommended maximum IOL for the -1 version is increased to 48 mA. There is no -1 version of the SN54ALS640B.
The SN54ALS640B and SN54AS640 are characterized for operation over the full military temperature range of -55°C to 125°C. The SN74ALS640B and SN74AS640 are characterized for operation from 0°C to 70°C.
| Supply voltage (min) (V) | 4.75 |
| Supply voltage (max) (V) | 5.25 |
| Number of channels | 8 |
| IOL (max) (mA) | 48 |
| IOH (max) (mA) | -15 |
| Input type | TTL |
| Output type | TTL |
| Features | High speed (tpd 10-50ns), Over-voltage tolerant inputs |
| Technology family | ALS |
| Rating | Catalog |
| Operating temperature range (°C) | 0 to 70 |
| PDIP (N) | 20 | 228.702 mm² 24.33 x 9.4 |
| SOIC (DW) | 20 | 131.84 mm² 12.8 x 10.3 |
| SOP (NS) | 20 | 98.28 mm² 12.6 x 7.8 |