Thermal Design User Guide: Agilex™ 5 FPGAs and SoCs

ID 814008
Date 9/30/2024
Public
Document Table of Contents

6.3. Example 3: Known Cooling Capacity

In this example, the goal is to determine the viability of a known cooling solution. Such determinations are especially useful when an FPGA is already in the field, or planned for a system with a known cooling solution. In both cases, ΨCA is a known value and can be entered in the PTC when you have selected a Calculation mode of Find available thermal margin for cooling solution.

This example assumes the same FPGA as in the previous examples. It is to be used in a design where the ΨCA is 2.8⁰ C/W.

By entering the ambient temperature and the known ΨCA value into the PTC, we can calculate the die thermal and power margins relative to the TJ-MAX of 100⁰ C. The figure below shows the results on the PTC Thermal tab. We can conclude that the power consumption of this FPGA can be increased by an additional 7 watts, while remaining within the limits of this cooling solution.

Figure 9. Thermal Results

You can also use the following equation to calculate TJ once the thermal parameters are known:

TJ = TA + TDP * (ΨJC + ΨCA)

TJ = 50 + 10 * (0.05 + 2.8) = 78.5