Thermal Design User Guide: Agilex™ 3 FPGAs and SoCs

ID 851249
Date 5/12/2025
Public
Document Table of Contents

7.2. Example 2: Find Available Thermal Margin for Cooling Solution

In this example, you have a thermal solution already assigned or available, and the thermal margin on the Agilex™ 3 device must be determined. The heat sink has an effective ΨCA of 20°C/W.

The module’s thermal solution includes a 50mm x 50mm x 25mm heat sink, no air flow and the device is on a 10-layer board.

From the table in the Variables Affecting the Heat Flow Path topic, we see that the percentage heat transfer to the heat sink is 55%.

To input the cooling solution ΨCA value into the PTC Thermal tab, you perform the following calculation:

In the PTC thermal tab, choose the calculation mode as Find available thermal margin for cooling solution.

Input the ΨCA of 11°C/W and the ambient temperature, T, of 50°C.

Figure 13. Example 2, PTC Main tab

This results in a thermal margin of 14.46°C.

This example illustrates that the available cooling solution is adequate for the system and device power. The cooling solution can be redesigned to a smaller/less effective one, if required.