SLVSGT4A December   2023  – January 2024 TPS61289

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Bidirectional Operation Configuration
      2. 6.3.2 VCC Power Supply
      3. 6.3.3 VHIGH and VCC Undervoltage Lockout (UVLO)
      4. 6.3.4 Enable and Programmable EN/UVLO
      5. 6.3.5 Switching Frequency
      6. 6.3.6 Programmable Switching Peak and Valley Current Limit
      7. 6.3.7 External Clock Synchronization
      8. 6.3.8 VHIGH Overvoltage Protection
      9. 6.3.9 Thermal Shutdown
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
        1. 7.2.2.1 Bootstrap Capacitor Selection
        2. 7.2.2.2 Inductor Selection
        3. 7.2.2.3 MOSFET Selection
        4. 7.2.2.4 VLOW/VHIGH Output Capacitor Selection
      3. 7.2.3 Application Curves
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      2. 7.4.2 Layout Example
        1. 7.4.2.1 Thermal Considerations
  9. 8 Device and Documentation Support
    1. 8.1 Documentation Support
      1. 8.1.1 Related Documentation
    2. 8.2 Receiving Notification of Documentation Updates
    3. 8.3 Support Resources
    4. 8.4 Trademarks
    5. 8.5 Electrostatic Discharge Caution
    6. 8.6 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

Package Options

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

6.3.5 Switching Frequency

The TPS61289 operates at a quasi-constant frequency pulse width modulation (PWM) mode. Based on the ratio of the VLOW voltage to the VHIGH voltage, a circuit predicts the required on or off time of the switching cycle.

When the VLOW pin voltage is higher than 1.7V, the TPS61289 operates at 250kHz switching frequency. When VLOW voltage falls below 1.5V, the frequency changes from 250kHz to 100kHz, when VLOW voltage rises above 1.7V, the frequency changes from 100kHz to 250kHz. When the VLOW voltage falls below 0.5V, the frequency changes from 100kHz to 50kHz, when the VLOW voltage rises above 0.7V, the frequency changes from 50kHz to 100kHz to improve the efficiency and extend the buck/boost ratio. The 200mV hysteresis prevents frequency jitter in the presence of VLOW pin voltage noise.