ZHCSH68G November 2017 – November 2024 UCC21220 , UCC21220A
PRODUCTION DATA
- 1
- 1 特性
- 2 應用
- 3 說明
- 4 Device Comparison Table
- 5 Pin Configuration and Functions
- 6 Specifications
- 7 Parameter Measurement Information
- 8 Detailed Description
-
9 Application and Implementation
- 9.1 Application Information
- 9.2
Typical Application
- 9.2.1 Design Requirements
- 9.2.2
Detailed Design Procedure
- 9.2.2.1 Designing INA/INB Input Filter
- 9.2.2.2 Select External Bootstrap Diode and its Series Resistor
- 9.2.2.3 Gate Driver Output Resistor
- 9.2.2.4 Estimating Gate Driver Power Loss
- 9.2.2.5 Estimating Junction Temperature
- 9.2.2.6 Selecting VCCI, VDDA/B Capacitor
- 9.2.2.7 Application Circuits with Output Stage Negative Bias
- 9.2.3 Application Curves
- 10Power Supply Recommendations
- 11Layout
- 12Device and Documentation Support
- 13Revision History
- 14Mechanical, Packaging, and Orderable Information
9.2.2.5 Estimating Junction Temperature
The junction temperature (TJ) of the UCC21220 and UCC21220A can be estimated with Equation 17:
where
- TC is the UCC21220 and UCC21220A case-top temperature measured with a thermocouple or some other instrument, ψJT is the junction-to-top characterization parameter from the Section 6.4 table. Importantly, ψJT is developed based on JEDEC standard PCB board and it is subject to change when the PCB board layout is different.
Using the junction-to-top characterization parameter (ΨJT) instead of the junction-to-case thermal resistance (RΘJC) can greatly improve the accuracy of the junction temperature estimation. The majority of the thermal energy of most ICs is released into the PCB through the package leads, whereas only a small percentage of the total energy is released through the top of the case (where thermocouple measurements are usually conducted). RΘJC can only be used effectively when most of the thermal energy is released through the case, such as with metal packages or when a heatsink is applied to an IC package. In all other cases, use of RΘJC will inaccurately estimate the true junction temperature. ΨJT is experimentally derived by assuming that the amount of energy leaving through the top of the IC will be similar in both the testing environment and the application environment. As long as the recommended layout guidelines are observed, junction temperature estimates can be made accurately to within a few degrees Celsius.
For more information, see the Section 11.1 and Semiconductor and IC Package Thermal Metrics Application Report.