SBOSA16 October   2020 OPA455


  1. Features
  2. Applications
  3. Description
  4. Revision History
  5. Pin Configuration and Functions
  6. Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  7. Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Status Flag Pin
      2. 7.3.2 Thermal Protection
      3. 7.3.3 Current Limit
      4. 7.3.4 Enable and Disable
    4. 7.4 Device Functional Modes
  8. Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 High DAC Gain Stage for Semiconductor Test Equipment
        1. Design Requirements
        2. Detailed Design Procedure
        3. Application Curve
      2. 8.2.2 Improved Howland Current Pump for Bioimpedance Measurements in Multiparameter Patient Monitors
        1. Design Requirements
        2. Detailed Design Procedure
  9. Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Thermally-Enhanced PowerPAD™ Package
      2. 10.1.2 PowerPAD™ Integrated Circuit Package Layout Guidelines
      3. 10.1.3 Pin Leakage
      4. 10.1.4 Thermal Protection
      5. 10.1.5 Power Dissipation
      6. 10.1.6 Heat Dissipation
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Development Support
        1. TINA-TI™ Simulation Software (Free Download)
        2. TI Precision Designs
        3. WEBENCH® Filter Designer
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Support Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

Thermally-Enhanced PowerPAD™ Package

The OPA455 comes in an 8-pin SO PowerPAD package that provides an extremely low thermal resistance, RθJC(bot), path between the die and the exterior of the package. This package features an exposed thermal pad that has direct thermal contact with the die. Thus, excellent thermal performance is achieved by providing a good thermal path away from the thermal pad.

The OPA455 SO-8 PowerPAD is a standard-size SO-8 package constructed using a downset leadframe upon which the die is mounted, as Figure 10-1 shows. This arrangement results in the leadframe being exposed as a thermal pad on the underside of the package. The thermal pad on the bottom of the device can then be soldered directly to the PCB, using the PCB as a heat sink. In addition, plated-through holes (vias) provide a low thermal resistance heat flow path to the back side of the PCB. This architecture enhances the OPA455 power dissipation capability significantly, eliminates the use of bulky heat sinks and slugs traditionally used in thermal packages, and allows the OPA455 to be easily mounted using standard PCB assembly techniques.


The SO-8 PowerPAD is pin-compatible with standard SO-8 packages, and as such, the OPA455 is a drop-in replacement for operational amplifiers in existing sockets. Always solder the PowerPAD to the PCB V– plane, even with applications that have low power dissipation. Solder the device to the PCB to provide the necessary thermal, mechanical, and electrical connections between the leadframe die pad and the PCB.

GUID-45F01533-3A0D-445E-81B2-24BA5C8D17C8-low.gifFigure 10-1 Cross Section View of a PowerPAD™ Package