SNVSA91F September   2015  – April 2021 LP5910

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 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. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 No-Load Stability
      2. 7.3.2 Thermal Overload Protection
      3. 7.3.3 Short-Circuit Protection
      4. 7.3.4 Output Automatic Discharge
      5. 7.3.5 Reverse Current Protection
    4. 7.4 Device Functional Modes
      1. 7.4.1 Enable (EN)
  8. 8 Applications 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 External Capacitors
        2. 8.2.2.2 Input Capacitor
        3. 8.2.2.3 Output Capacitor
        4. 8.2.2.4 Capacitor Characteristics
        5. 8.2.2.5 Remote Capacitor Operation
        6. 8.2.2.6 No-Load Stability
        7. 8.2.2.7 Enable Control
        8. 8.2.2.8 Power Dissipation
        9. 8.2.2.9 Estimating Junction Temperature
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 DSBGA Mounting
      2. 10.1.2 DSBGA Light Sensitivity
    2. 10.2 Layout Examples
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    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

Package Options

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

8.2.2.8 Power Dissipation

Knowing the device power dissipation and proper sizing of the thermal plane connected to the tab or pad is critical to ensuring reliable operation. Device power dissipation depends on input voltage, output voltage, and load conditions and can be calculated with Equation 1.

Equation 1. PD(MAX) = (VIN(MAX) – VOUT) × IOUT(MAX)

Power dissipation can be minimized, and greater efficiency can be achieved, by using the lowest available voltage drop option that would still be greater than the dropout voltage (VDO). However, keep in mind that higher voltage drops result in better dynamic (that is, PSRR and transient) performance.

On the WSON (DRV) package, the primary conduction path for heat is through the exposed power pad to the PCB. To ensure the device does not overheat, connect the exposed pad, through thermal vias, to an internal ground plane with an appropriate amount of copper PCB area .

On the DSBGA (YKA) package, the primary conduction path for heat is through the four bumps to the PCB.

The maximum allowable junction temperature (TJ(MAX)) determines maximum power dissipation allowed (PD(MAX)) for the device package.

Power dissipation and junction temperature are most often related by the junction-to-ambient thermal resistance (RθJA) of the combined PCB and device package and the temperature of the ambient air (TA), according to Equation 2 or Equation 3:

Equation 2. TJ(MAX) = TA(MAX) + (RθJA × PD(MAX))
Equation 3. PD(MAX) = (TJ(MAX) - TA(MAX)) / RθJA

Unfortunately, this RθJA is highly dependent on the heat-spreading capability of the particular PCB design, and therefore varies according to the total copper area, copper weight, and location of the planes. The RθJA recorded in Section 6.4 is determined by the specific EIA/JEDEC JESD51-7 standard for PCB and copper-spreading area, and is to be used only as a relative measure of package thermal performance. For a well-designed thermal layout, RθJA is actually the sum of the package junction-to-case (bottom) thermal resistance (RθJCbot) plus the thermal resistance contribution by the PCB copper area acting as a heat sink.