SNVSA58C January   2015  – November 2017 LM26480-Q1

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison Tables
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1  Absolute Maximum Ratings
    2. 7.2  ESD Ratings
    3. 7.3  Recommended Operating Conditions: Bucks
    4. 7.4  Thermal Information
    5. 7.5  General Electrical Characteristics
    6. 7.6  Low Dropout Regulators, LDO1 and LDO2
    7. 7.7  Buck Converters SW1, SW2
    8. 7.8  I/O Electrical Characteristics
    9. 7.9  Power-On Reset Threshold/Function (POR)
    10. 7.10 Typical Characteristics — LDO
    11. 7.11 Typical Characteristics — Buck 2.8 V to 5.5 V
    12. 7.12 Typical Characteristics — Bucks 1 and 2
    13. 7.13 Typical Characteristics — Buck 3.6 V
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 DC-DC Converters
        1. 8.3.1.1 Linear Low Dropout Regulators (LDOs)
          1. 8.3.1.1.1 No-Load Stability
        2. 8.3.1.2 SW1, SW2: Synchronous Step-Down Magnetic DC-DC Converters
          1. 8.3.1.2.1  Functional Description
          2. 8.3.1.2.2  Circuit Operation Description
          3. 8.3.1.2.3  PWM Operation
          4. 8.3.1.2.4  Internal Synchronous Rectification
          5. 8.3.1.2.5  Current Limiting
          6. 8.3.1.2.6  PFM Operation
          7. 8.3.1.2.7  SW1, SW2 Control
          8. 8.3.1.2.8  Shutdown Mode
          9. 8.3.1.2.9  Soft Start
          10. 8.3.1.2.10 Low Dropout Operation
          11. 8.3.1.2.11 Flexible Power-On Reset (Power Good with Delay)
          12. 8.3.1.2.12 Undervoltage Lockout
    4. 8.4 Device Functional Modes
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 External Component Selection
      2. 9.1.2 Feedback Resistors for LDOs
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
        1. 9.2.1.1 High VIN- High Load Operation
        2. 9.2.1.2 Junction Temperature
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Custom Design With WEBENCH® Tools
        2. 9.2.2.2 Output Inductors and Capacitors for SW1 AND SW2
          1. 9.2.2.2.1 Inductor Selection for SW1 and SW2
          2. 9.2.2.2.2 Suggested Inductors and Their Suppliers
        3. 9.2.2.3 Output Capacitor Selection for SW1 and SW2
        4. 9.2.2.4 Input Capacitor Selection for SW1 and SW2
        5. 9.2.2.5 LDO Capacitor Selection
          1. 9.2.2.5.1 Input Capacitor
          2. 9.2.2.5.2 Output Capacitor
          3. 9.2.2.5.3 Capacitor Characteristics
      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 Device Support
      1. 12.1.1 Third-Party Products Disclaimer
    2. 12.2 Documentation Support
      1. 12.2.1 Custom Design With WEBENCH® Tools
      2. 12.2.2 Related Documentation
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Community Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

10 Power Supply Recommendations

All power inputs should be tied to the main VDD source (that is, a battery), unless the user wishes to power it from another source. (that is, powering LDO from Buck output).

The analog VDD inputs power the internal bias and error amplifiers, so they should be tied to the main VDD. The analog VDD inputs must have an input voltage between 2.8 V and 5.5 V, as specified in the Recommended Operating Conditions: Bucks section of this datasheet.

The other VIN pins (VINLDO1, VINLDO2, VIN1, VIN2) can actually have inputs lower than 2.8 V, as long as they are higher than the programmed output (0.3 V). The analog and digital grounds should be tied together outside of the chip to reduce noise coupling.