SCLSA02 March   2024 SN74AHC257-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6.   6
  7.   7
  8. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Switching Characteristics
    7. 5.7 Noise Characteristics
    8. 5.8 Typical Characteristics
  9. 6 Parameter Measurement Information
  10. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Balanced CMOS 3-State Outputs
      2. 7.3.2 Standard CMOS Inputs
      3. 7.3.3 Wettable Flanks
      4. 7.3.4 Clamp Diode Structure
    4. 7.4 Device Functional Modes
  11. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
    3. 8.3 Design Requirements
      1. 8.3.1 Power Considerations
      2. 8.3.2 Input Considerations
      3. 8.3.3 Output Considerations
    4. 8.4 Detailed Design Procedure
    5. 8.5 Application Curve
    6. 8.6 Power Supply Recommendations
    7. 8.7 Layout
      1. 8.7.1 Layout Guidelines
      2. 8.7.2 Layout Example
  12. 9 Device and Documentation Support
    1. 9.1 Receiving Notification of Documentation Updates
    2. 9.2 Support Resources
    3. 9.3 Trademarks
    4. 9.4 Electrostatic Discharge Caution
    5. 9.5 Glossary
  13. 10Revision History
  14. 11Mechanical, Packaging, and Orderable Information

Package Options

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

8.3.1 Power Considerations

Ensure the desired supply voltage is within the range specified in the Recommended Operating Conditions. The supply voltage sets the device's electrical characteristics as described in the Electrical Characteristics section.

The positive voltage supply must be capable of sourcing current equal to the total current to be sourced by all outputs of the SN74AHC257-Q1 plus the maximum static supply current, ICC, listed in the Electrical Characteristics, and any transient current required for switching. The logic device can only source as much current that is provided by the positive supply source. Ensure the maximum total current through VCC listed in the Absolute Maximum Ratings is not exceeded.

The ground must be capable of sinking current equal to the total current to be sunk by all outputs of the SN74AHC257-Q1 plus the maximum supply current, ICC, listed in the Electrical Characteristics, and any transient current required for switching. The logic device can only sink as much current that can be sunk into its ground connection. Ensure the maximum total current through GND listed in the Absolute Maximum Ratings is not exceeded.

The SN74AHC257-Q1 can drive a load with a total capacitance less than or equal to 50pF while still meeting all of the data sheet specifications. Larger capacitive loads can be applied; however, it is not recommended to exceed 50pF.

The SN74AHC257-Q1 can drive a load with total resistance described by RL ≥ VO / IO, with the output voltage and current defined in the Electrical Characteristics table with VOH and VOL. When outputting in the HIGH state, the output voltage in the equation is defined as the difference between the measured output voltage and the supply voltage at the VCC pin.

Total power consumption can be calculated using the information provided in CMOS Power Consumption and Cpd Calculation.

Thermal increase can be calculated using the information provided in Thermal Characteristics of Standard Linear and Logic (SLL) Packages and Devices.

CAUTION: The maximum junction temperature, TJ(max) listed in the Absolute Maximum Ratings, is an additional limitation to prevent damage to the device. Do not violate any values listed in the Absolute Maximum Ratings. These limits are provided to prevent damage to the device.