SLVSK53 October 2025 TPS7E82
ADVANCE INFORMATION
- 1
- 1 Features
- 2 Applications
- 3 Description
- 4 Pin Configuration and Functions
- 5 Specifications
- 6 Detailed Description
-
7 Application and Implementation
- 7.1
Application Information
- 7.1.1 Adjustable Device Feedback Resistor Selection
- 7.1.2 Recommended Capacitor Types
- 7.1.3 Input and Output Capacitor Selection
- 7.1.4 Reverse Current
- 7.1.5 Feed-Forward Capacitor
- 7.1.6 Dropout Voltage
- 7.1.7 Estimating Junction Temperature
- 7.1.8 Power Dissipation (PD)
- 7.1.9 Power Dissipation Versus Ambient Temperature
- 7.2 Typical Application
- 7.1
Application Information
- 8 Device and Documentation Support
- 9 Revision History
- 10Mechanical, Packaging, and Orderable Information
7.1.7 Estimating Junction Temperature
The JEDEC standard now recommends using psi (Ψ) thermal metrics to estimate the LDO junction temperatures when in-circuit on a typical PCB board application. These metrics are not strictly speaking thermal resistances, but rather offer practical and relative means of estimating junction temperatures. These psi metrics are determined to be significantly independent of the copper-spreading area. The key thermal metrics (ΨJT and ΨJB) are used in accordance with Equation 8 and are given in the Section 5.5 table.
where:
- PD is the power dissipated as explained in Equation 8
- TT is the temperature at the center-top of the device package
- TB is the PCB surface temperature measured 1mm from the device package and centered on the package edge
The JEDEC standard now recommends using psi (Ψ) thermal metrics to estimate the linear regulator junction temperatures when in-circuit on a typical PCB board application. These metrics are not thermal resistance parameters and instead offer a practical and relative way to estimate junction temperature. These psi metrics are determined to be significantly independent of the copper area available for heat-spreading. The Section 5.4 table lists the primary thermal metrics, which are the junction-to-top characterization parameter (ψJT) and junction-to-board characterization parameter (ψJB). These parameters provide two methods for calculating the junction temperature (TJ), as described in the following equations. Use the junction-to-top characterization parameter (ψJT) with the temperature at the center-top of device package (TT) to calculate the junction temperature. Use the junction-to-board characterization parameter (ψJB) with the printed circuit board (PCB) surface temperature 1mm from the device package (TB) to calculate the junction temperature.
where:
- PD is the dissipated power
- TT is the temperature at the center-top of the device package
where:
- TB is the PCB surface temperature measured 1mm from the device package and centered on the package edge
For detailed information on the thermal metrics and how to use the metrics, see the Semiconductor and IC Package Thermal Metrics application note.