SLVSI54 May   2025 TPS60800-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  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 Charge-Pump Output Resistance
      2. 7.3.2 Efficiency Considerations
    4. 7.4 Device Functional Modes
      1. 7.4.1 Active-Schottky Diode
  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 Capacitor Selection
        2. 8.2.2.2 Input Capacitor (CI)
        3. 8.2.2.3 Flying Capacitor (C(fly))
        4. 8.2.2.4 Output Capacitor (CO)
        5. 8.2.2.5 Power Dissipation
      3. 8.2.3 Application Curve
    3. 8.3 System Examples
      1. 8.3.1 RC-Post Filter
      2. 8.3.2 Rail Splitter
      3. 8.3.3 Combined Doubler, Inverter
      4. 8.3.4 Cascading Devices
      5. 8.3.5 Paralleling Devices
      6. 8.3.6 Step-Down Charge Pump
    4. 8.4 Power Supply Recommendations
    5. 8.5 Layout
      1. 8.5.1 Layout Guidelines
      2. 8.5.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Device Support
      1. 9.1.1 Third-Party Products Disclaimer
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

8.2.2.5 Power Dissipation

As given in Thermal Information, the thermal resistance RΘJB of TPS60800-Q1 is 109.1°C/W. RΘJB refers to the thermal resistance between the device junction temperature and the surrounding board temperature. The following equations calculate the highest allowable board temperature under full power conditions, subject to the device junction temperature not exceeding 125°C.

The thermal resistance RΘJB can be calculated using Equation 7.

Equation 7. R θ J B = T J   -   T B P D

where:

TJ is the junction temperature, TB is the board temperature and PD is the power dissipated by the device.

The maximum power dissipation can be calculated by using the following Equation 8.

Equation 8. P D =   V I × I I - V O × I O   =   V I ( m a x ) × I O + I ( S u p p l y ) -   V O × I O  

The maximum power dissipation happens with maximum input voltage and maximum output current.

At maximum load the maximum supply current is 1mA (see Equation 9).

Equation 9. P D =   5 V × ( 200 m A   + 1 m A ) - 4.15 V × 200 m A   =   175 m W

With this maximum power rating and thermal resistance, RΘJB, the maximum junction temperature rise above the board temperature can be calculated using Equation 10.

Equation 10. ∆ T J = R θ J B × P D   =   109.1 ℃ / W × 175 m W   =   19.09 ℃

This equation means that the power dissipation increases TJ by < 20°C with respect to the board temperature.

The junction temperature of the device must not exceed 125°C.

This limit implies the IC can easily be used up to board temperatures given by Equation 11.

Equation 11. T B = T J ( m a x ) - ∆ T J   =   125 ℃   -   20 ℃   =   105 ℃