SLVSE48C january   2018  – may 2023 TPS65268-Q1

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 Timing Requirements
    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  Adjusting the Output Voltage
      2. 7.3.2  Enable and Adjusting UVLO
      3. 7.3.3  Soft-Start Time
      4. 7.3.4  Power-Up Sequencing
      5. 7.3.5  V7V Low-Dropout Regulator and Bootstrap
      6. 7.3.6  Out-of-Phase Operation
      7. 7.3.7  Output Overvoltage Protection (OVP)
      8. 7.3.8  Slope Compensation
      9. 7.3.9  Overcurrent Protection
        1. 7.3.9.1 High-Side MOSFET Overcurrent Protection
        2. 7.3.9.2 Low-Side MOSFET Overcurrent Protection
      10. 7.3.10 Power Good
        1. 7.3.10.1 Adjustable Switching Frequency
      11. 7.3.11 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Normal Operation
      2. 7.4.2 Standby 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 Output Inductor Selection
        2. 8.2.2.2 Output Capacitor Selection
        3. 8.2.2.3 Input Capacitor Selection
        4. 8.2.2.4 Loop Compensation
      3. 8.2.3 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Receiving Notification of Documentation Updates
    2. 9.2 Support Resources
    3. 9.3 Trademarks
    4. 9.4 Electrostatic Discharge Caution
    5. 9.5 Glossary
  11. 10Mechanical, Packaging, and Orderable Information

Package Options

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

7.3.2 Enable and Adjusting UVLO

The ENx pin provides electrical on and off control of the device. After the ENx pin voltage exceeds the threshold voltage, the device starts operation. If each ENx pin voltage is pulled below the threshold voltage, the regulator stops switching and enters a low quiescent-current (IQ) state.

The ENx pin has an internal pullup current source, allowing the user to float the ENx pin to enable the device. If an application requires controlling the ENx pin, use open-drain or open-collector output logic to interface with the pin.

The device implements internal UVLO circuitry on the VIN pin. The device is disabled when the VIN pin voltage falls below the internal UVLO threshold of the input voltage. The internal UVLO threshold of the input voltage has a hysteresis of 500 mV. If an application requires either a higher UVLO threshold on the VIN pin or a secondary UVLO on the PVINx in split-rail applications, then the user can configure the ENx pin as shown in Figure 7-2, Figure 7-3, and Figure 7-4. When using the external UVLO function, TI recommends setting the hysteresis higher than 500 mV.

The ENx pin has a small pullup current, Ip, which sets the default state of the pin to enable when no external components are connected. The pullup current is also used to control the voltage hysteresis for the UVLO function because it increases by Ih after the ENx pin crosses the enable threshold. Use Equation 2 and Equation 3 to calculate the UVLO thresholds.

Equation 2. GUID-4D340C3F-7251-44B9-9011-0483AFF21B6C-low.gif
Equation 3. GUID-1252FB98-A830-4891-8CCE-BABFCDC4127B-low.gif

where

  • Ih = 3 µA
  • Ip = 3.9 µA
  • VENRISING = 1.2 V
  • VENFALLING = 1.15 V
GUID-041654FD-AC56-4C10-B37D-BD8F659B8DEA-low.gifFigure 7-2 Adjustable VIN UVLO
GUID-BB1DB4EF-DF82-42B0-A05E-06256392F2D0-low.gifFigure 7-4 Adjustable VIN and PVIN UVLO
GUID-9EC87E50-D5C9-40DE-BB0A-81D880784C7B-low.gifFigure 7-3 Adjustable PVIN UVLO, VIN > 4 V