SCHS192C November   1998  – July 2022 CD54HC640 , CD54HCT640 , CD74HC640 , CD74HCT640

PRODUCTION DATA  

  1. 1 Features
  2. 2 Description
  3. 3 Revision History
  4. 4 Pin Configuration and Functions
  5. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 Recommended Operating Conditions
    3. 5.3 Thermal Information
    4. 5.4 Electrical Characteristics
    5. 5.5 Switching Characteristics (2)
  6. 6 Parameter Measurement Information
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Device Functional Modes
  8. 8 Power Supply Recommendations
  9. 9 Layout
    1. 9.1 Layout Guidelines
  10. 10Device and Documentation Support
    1. 10.1 Documentation Support
      1. 10.1.1 Related Documentation
    2. 10.2 Receiving Notification of Documentation Updates
    3. 10.3 Support Resources
    4. 10.4 Trademarks
    5. 10.5 Electrostatic Discharge Caution
    6. 10.6 Glossary
  11. 11Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • J|20
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.1 Overview

The CDx4HC640 and CDx4HCT640 silicon-gate CMOS three-state bidirectional inverting and non-inverting buffers are intended for two-way asynchronous communication between data buses. They have high drive current outputs which enable high-speed operation when driving large bus capacitances. These circuits possess the low power dissipation of CMOS circuits, and have speeds comparable to low power Schottky TTL circuits. They can drive 15 LSTTL loads. The CDx4HC640 and CDx4HCT640 devices have inverting buffers.

The direction of data flow (A to B, B to A) is controlled by the DIR input.

Outputs are enabled by a low on the Output Enable input (OE); a high OE puts these devices in the high impedance mode.