SLVSCJ5C December   2015  – September 2024 TPS7H3301-SP

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 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 VTT/VO Sink and Source Regulator
      2. 7.3.2 Reference Input (VDDQSNS)
      3. 7.3.3 Reference Output (VTTREF)
      4. 7.3.4 EN Control (EN)
      5. 7.3.5 Power-Good Function (PGOOD)
      6. 7.3.6 VTT Current Protection
      7. 7.3.7 VIN UVLO Protection
      8. 7.3.8 Thermal Shutdown
    4. 7.4 Device Functional Modes
  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 VDD/VIN Capacitor
        2. 8.2.2.2 VLDO Input Capacitor
        3. 8.2.2.3 VTT Output Capacitor
        4. 8.2.2.4 VTTSNS Connection
        5. 8.2.2.5 Low VIN Applications
        6. 8.2.2.6 S3 and Pseudo-S5 Support
        7. 8.2.2.7 Tracking Startup and Shutdown
        8. 8.2.2.8 Output Tolerance Consideration for VTT DIMM or Module Applications
        9. 8.2.2.9 LDO Design Guidelines
      3. 8.2.3 Application Curve
  10.   Power Supply Recommendations
  11. 9 Layout
    1. 9.1 Layout Guidelines
    2. 9.2 Layout Example
    3. 9.3 Thermal Considerations
  12. 10Device and Documentation Support
    1. 10.1 Device Support
      1. 10.1.1 Third-Party Products Disclaimer
    2. 10.2 Documentation Support
      1. 10.2.1 Related Documentation
    3. 10.3 Receiving Notification of Documentation Updates
    4. 10.4 Support Resources
    5. 10.5 Trademarks
    6. 10.6 Electrostatic Discharge Caution
    7. 10.7 Glossary
  13.   Mechanical, Packaging, and Orderable Information

9.3 Thermal Considerations

VTT/VO current can flow in both source and sink directions. As the TPS7H3301-SP is a linear regulator, power is dissipated internal to the device. When the device is sourcing current, the voltage difference between VLDOIN and VTT/VO times IO (IIO ) current becomes the power dissipation as shown in Equation 2.

Equation 2. TPS7H3301-SP

In this case, if VLDOIN is connected to an alternative power supply lower than the VDDQ voltage, overall power loss can be reduced. For the sink phase, VO voltage is applied across the internal LDO regulator and the power dissipation (PDISS_SNK) can be calculated by Equation 3.

Equation 3. TPS7H3301-SP

Because the device does not sink and source current at the same time and the IO current may vary rapidly with time, the actual power dissipation should be the time average of the above dissipations over the thermal relaxation duration of the system. Another source of power consumption is the current used for the internal current control circuitry from the VDD/VIN supply and the VLDOIN supply. This can be estimated as PVDD/VIN = 105mW and PVLODIN = 4.2mW or less during normal operating conditions. This power must be effectively dissipated from the package.

The thermal performance of an LDO depends on the printed circuit board (PCB) layout. Because the TPS7H3301-SP device is shipped unformed, only the recommended heat pad pattern is shown. Lead pad placement depends on final form factor.

To further improve the thermal performance of this device, using a larger than recommended thermal land as well as increasing the number of vias helps lower the thermal resistance from junction to heat slug.