SN74ALS640B Octal Bus Transceivers |

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Octal Bus Transceivers

Octal Bus Transceivers - SN74ALS640B


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.




  • Bidirectional Bus Transceivers in High-Density 20-Pin Packages
  • Inverting Logic
  • Package Options Include Plastic Small-Outline (DW) Packages, Ceramic Chip Carriers (FK), and Standard Plastic (N) and Ceramic (J) 300-mil DIPs



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Part number Order Technology Family VCC (Min) (V) VCC (Max) (V) Bits (#) Voltage (Nom) (V) F @ nom voltage (Max) (MHz) ICC @ nom voltage (Max) (mA) tpd @ nom Voltage (Max) (ns) IOL (Max) (mA) IOH (Max) (mA) Rating Operating temperature range (C)
SN74ALS640B Order now ALS     4.5     5.5     8     5     75     55     11     24     -15     Catalog     0 to 70    
SN54ALS640B Samples not available ALS     4.5     5.5     8     5     75     55     11     24     -15     Military     -55 to 125