SCAS218X January   1993  – January 2015 SN74LVC245A

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Simplified Schematic
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Thermal Information
    4. 6.4 Typical Characteristics
  7. 7 Parameter Measurement Information
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
    4. 8.4 Device Functional Modes
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • DGV|20
  • DB|20
  • NS|20
  • N|20
  • DW|20
  • PW|20
  • RGY|20
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8 Detailed Description

8.1 Overview

This octal bus transceiver is designed for 1.65-V to 3.6-V VCC operation.

The SN74LVC245A device is designed for asynchronous communication between data buses. This device transmits data from the A bus to the B bus or from the B bus to the A bus, depending on the logic level at the direction-control (DIR) input. The output-enable (OE) input can be used to disable the device so the buses effectively are isolated.

To ensure the high-impedance state during power up or power down, OE should be tied to VCC through a pull-up resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver.

Inputs can be driven from either 3.3-V or 5-V devices. This feature allows the use of this device as a translator in a mixed 3.3-V/5-V system environment.

This device is fully specified for partial-power-down applications using Ioff. The Ioff circuitry disables the outputs, preventing damaging current backflow through the device when it is powered down.

8.2 Functional Block Diagram

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8.3 Feature Description

  • Allows down voltage translation
    • 5 V to 3.3 V
    • 5 V or 3.3 V to 1.8 V
  • Inputs accept voltage levels up to 5.5 V

8.4 Device Functional Modes

Table 1. Function Table

INPUTS OPERATION
OE DIR
L L B data to A bus
L H A data to B bus
H X Isolation