SBOS070D October   1997  – December 2019 OPA548

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
    1.     Simplified Schematic
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 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. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Adjustable Current Limit
      2. 7.3.2 Enable/Status (E/S) Pin
      3. 7.3.3 Thermal Shutdown Status
    4. 7.4 Device Functional Modes
      1. 7.4.1 Output Disable
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Basic Circuit Connections
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Power Supply Requirements
          2. 8.2.1.2.2 Gain Setting and Input Configuration
          3. 8.2.1.2.3 Current Limit
          4. 8.2.1.2.4 Safe-Operating-Area
          5. 8.2.1.2.5 Heat Sinking
        3. 8.2.1.3 Application Curve
      2. 8.2.2 Monitoring Single- and Dual-Supplies
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
          1. 8.2.2.2.1 Output Disable and Thermal Shutdown Status
      3. 8.2.3 Programmable Power Supply
    3. 8.3 System Examples
  9. 9 Power Supply Recommendations
    1. 9.1 Output Stage Compensation
    2. 9.2 Output Protection
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Safe Operating Area
      2. 10.1.2 Amplifier Mounting
      3. 10.1.3 Power Dissipation
      4. 10.1.4 Thermal Considerations
      5. 10.1.5 Heat Sinking
        1. 10.1.5.1 Heat Sink Selection Example
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Support Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

7.3.1 Adjustable Current Limit

The OPA548 features an accurate, user-selected current limit. The current limit is set from 0 A to 5 A by controlling the input to the ILIM pin. Unlike other designs, which use a power resistor in series with the output current path, the OPA548 senses the load indirectly. This allows the current limit to be set with a 0-μA to 330-μA control signal. In contrast, other designs require a limiting resistor to handle the full output current (5 A in this case).

With the OPA548, the simplest method for adjusting the current limit uses a resistor or potentiometer connected between the ILIM pin and V– according to the Equation 1:

Equation 1. OPA548 Eq1_RCL_sbos070.gif

The low-level control signal (0 μA to 330 μA) also allows the current limit to be digitally controlled.

See Figure 41 for a simplified schematic of the internal circuitry used to set the current limit. Leaving the ILIM pin open programs the output current to zero, while connecting ILIM directly to V– programs the maximum output current limit, typically 5 A.