SNVS677H May   2011  – October 2023 LMZ10501

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  6. 5 Pin Configuration and Functions
  7. 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 System Characteristics
    7. 6.7 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Current Limit
      2. 7.3.2 Startup Behavior and Soft Start
      3. 7.3.3 Output Short Circuit Protection
      4. 7.3.4 Thermal Overload Protection
    4. 7.4 Device Functional Modes
      1. 7.4.1 Circuit Operation
      2. 7.4.2 Input Under Voltage Detection
      3. 7.4.3 Shutdown Mode
      4. 7.4.4 EN Pin Operation
      5. 7.4.5 Internal Synchronous Rectification
      6. 7.4.6 High Duty Cycle Operation
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Custom Design With WEBENCH® Tools
        2. 8.2.2.2 Setting The Output Voltage
          1. 8.2.2.2.1 RT And RB Selection For Fixed VOUT
          2. 8.2.2.2.2 Output Voltage Accuracy Optimization
        3. 8.2.2.3 Dynamic Output Voltage Scaling
        4. 8.2.2.4 Integrated Inductor
        5. 8.2.2.5 Input And Output Capacitor Selection
      3. 8.2.3 Application Curves
        1. 8.2.3.1 VOUT = 1.2 V
        2. 8.2.3.2 VOUT = 1.8 V
        3. 8.2.3.3 VOUT = 2.5 V
        4. 8.2.3.4 VOUT = 3.3 V
    3. 8.3 Power Supply Recommendations
      1. 8.3.1 Voltage Range
      2. 8.3.2 Current Capability
      3. 8.3.3 Input Connection
        1. 8.3.3.1 Voltage Drops
        2. 8.3.3.2 Stability
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
      3. 8.4.3 Package Considerations
  10. 9 Device and Documentation Support
    1. 9.1 Device Support
      1. 9.1.1 Custom Design With WEBENCH® Tools
    2. 9.2 Documentation Support
      1. 9.2.1 Related Documentation
    3. 9.3 Receiving Notification of Documentation Updates
    4. 9.4 Support Resources
    5. 9.5 Trademarks
    6. 9.6 Electrostatic Discharge Caution
    7. 9.7 Glossary
  11. 10Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • SIL|8
Thermal pad, mechanical data (Package|Pins)
Orderable Information
8.2.2.2.1 RT And RB Selection For Fixed VOUT

The parameters affecting the output voltage setting are the RT, RB, and the product of the VREF voltage × GAIN. The VREF voltage is typically 2.35V. Because VCON is derived from VREF through RT and RB,

Equation 2. VCON = VREF × RB/ (RB + RT)

After substitution,

Equation 3. VOUT = VREF × GAIN × RB/ (RB + RT)
Equation 4. RT = (GAIN x VREF / VOUT – 1) × RB

The ideal product of GAIN × VREF = 5.875 V.

Choose RT to be between 80kΩ and 300kΩ. Then, RB can be calculated using Equation 5 below.

Equation 5. RB = (VOUT / (5.875 V – VOUT)) × RT

Note that the resistance of RT must be ≥ 80kΩ. This ensures that the VREF output current loading is not exceeded and the reference voltage is maintained. The current loading on VREF must not be greater than 30 µA.