SLVSFM1 March   2021 TPS62902

PRODUCTION DATA  

  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 Mode Selection and Device Configuration MODE/S-CONF
      2. 7.3.2 Adjustable VO Operation (External Voltage Divider)
      3. 7.3.3 Setable VO Operation (VSET and Internal Voltage Divider)
      4. 7.3.4 Soft Start / Tracking (SS/TR)
      5. 7.3.5 Smart Enable with Precise Threshold
      6. 7.3.6 Power Good (PG)
      7. 7.3.7 Undervoltage Lockout (UVLO)
      8. 7.3.8 Current Limit And Short Circuit Protection
      9. 7.3.9 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Pulse Width Modulation (PWM) Operation
      2. 7.4.2 AEE (Automatic Efficiency Enhancement)
      3. 7.4.3 Power Save Mode Operation (Auto PFM/PWM)
      4. 7.4.4 100% Duty-Cycle Operation
      5. 7.4.5 Output Discharge Function
      6. 7.4.6 Starting into a Pre-Biased Load
  8. Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application with Adjustable Output Voltage
      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 Programming the Output Voltage
        3. 8.2.2.3 External Component Selection
        4. 8.2.2.4 Inductor Selection
        5. 8.2.2.5 Capacitor Selection
          1. 8.2.2.5.1 Output Capacitor
          2. 8.2.2.5.2 Input Capacitor
          3. 8.2.2.5.3 Soft-Start Capacitor
        6. 8.2.2.6 Tracking Function
        7. 8.2.2.7 Output Filter and Loop Stability
      3. 8.2.3 Application Curves
      4. 8.2.4 Typical Application with Setable VO using VSET
        1. 8.2.4.1 Design Requirements
        2. 8.2.4.2 Detailed Design Procedure
        3. 8.2.4.3 Application Curves
    3. 8.3 System Examples
      1. 8.3.1 LED Power Supply
      2. 8.3.2 Powering Multiple Loads
      3. 8.3.3 Voltage Tracking
      4. 8.3.4 Precise Soft-Start Timing
  9. Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
      1. 10.2.1 Thermal Considerations
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Development Support
        1. 11.1.1.1 Custom Design With WEBENCH® Tools
    2. 11.2 Receiving Notification of Documentation Updates
    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)
  • RPJ|9
Thermal pad, mechanical data (Package|Pins)
Orderable Information

Powering Multiple Loads

In applications where the TPS62902 is used to power multiple load circuits, the total capacitance on the output can be very large. In order to properly regulate the output voltage, there needs to be an appropriate AC signal level on the VOS pin. Tantalum capacitors have a large enough ESR to keep output voltage ripple sufficiently high on the VOS pin. With low-ESR ceramic capacitors, the output voltage ripple can get very low, so it is not recommended to use a large capacitance directly on the output of the device. If there are several load circuits with their associated input capacitor on a pcb, these loads are typically distributed across the board. This adds enough trace resistance (Rtrace) to keep a large enough AC signal on the VOS pin for proper regulation.

The minimum total trace resistance on the distributed load is 10 mΩ. The total capacitance n x CIN in the use case below was 32 × 47 μF of ceramic X7R capacitors.

GUID-20201112-CA0I-TGRV-PZZG-CGN2G0KNF1D6-low.gif Figure 8-81 Multiple Loads