Thermal Design User Guide: Agilex™ 3 FPGAs and SoCs

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ID 851249
Date 5/12/2025
Public
Document Table of Contents
Document Table of Contents x
1. Introduction to Agilex™ 3 FPGA Thermal Design Guidelines 2. Agilex™ 3 FPGA Mechanical Construction 3. Agilex™ 3 FPGA Compact Thermal Model (CTM) Construction 4. Power and Thermal Calculator (PTC) 5. Thermal Design Process 6. General FPGA Thermal Design Considerations 7. Design Examples 8. Heat Sinks 9. Document Revision History for the Thermal Design User Guide: Agilex™ 3 FPGAs and SoCs A. Agilex™ 3 FPGA Product Keys and Package Drawings
1. Introduction to Agilex™ 3 FPGA Thermal Design Guidelines x
1.1. Thermal Design Requirements 1.2. Thermal Design Flow 1.3. Definitions of Thermal and Power Terms Used in this Document
2. Agilex™ 3 FPGA Mechanical Construction x
2.1. Built-in Temperature Sensors
2.1. Built-in Temperature Sensors x
2.1.1. Agilex™ 3 FPGA Temperature Rating
3. Agilex™ 3 FPGA Compact Thermal Model (CTM) Construction x
3.1. CTM File Format 3.2. Thermal Modeling with the CTM 3.3. CTM Top Temperature, TCASE Virtual Sensor 3.4. Obtaining the CTM
4. Power and Thermal Calculator (PTC) x
4.1. PTC Thermal Tab Parameters 4.2. Thermal Analysis with the PTC 4.3. PTC Thermal Tab Calculation Options 4.4. Thermal Resistances and Low Power Devices 4.5. Sensor Temperatures on the PTC Thermal Tab
5. Thermal Design Process x
5.1. Package Heat Flow Path 5.2. Variables Affecting the Heat Flow Path 5.3. Recommended Thermal Design Method
6. General FPGA Thermal Design Considerations x
6.1. FPGA Power Considerations
6.1. FPGA Power Considerations x
6.1.1. FPGA Maximum Allowed Power Dissipation 6.1.2. Static, Dynamic, and Standby Power 6.1.3. Future-Proofing an FPGA Thermal Design
7. Design Examples x
7.1. Example 1: Find Cooling Solution for Maximum Junction Temperature Limit 7.2. Example 2: Find Available Thermal Margin for Cooling Solution 7.3. Example 3: Find the Ambient Temperature for a Specified Cooling Solution
8. Heat Sinks x
8.1. Attachment Force 8.2. Thermal Interface Material (TIM)
8.2. Thermal Interface Material (TIM) x
8.2.1. Common TIM2 Materials
8.2.1. Common TIM2 Materials x
8.2.1.1. TIM2 Performance Parameters And Challenges 8.2.1.2. Understanding Resistance and Pressure Map Curves
1. Introduction to Agilex™ 3 FPGA Thermal Design Guidelines
2. Agilex™ 3 FPGA Mechanical Construction
3. Agilex™ 3 FPGA Compact Thermal Model (CTM) Construction
4. Power and Thermal Calculator (PTC)
5. Thermal Design Process
6. General FPGA Thermal Design Considerations
7. Design Examples
8. Heat Sinks
9. Document Revision History for the Thermal Design User Guide: Agilex™ 3 FPGAs and SoCs
A. Agilex™ 3 FPGA Product Keys and Package Drawings

5.2. Variables Affecting the Heat Flow Path

Many variables affect the portion of heat that gets dissipated into the PCB.

For purposes of determining the approximate heat flow split for a given use case, the following tables list a set of variables and ranges and their calculated impact on the heat flow path.

Table 4.  Variables Affecting Heat Flow Path From the FPGA
  Airflow (lfm) Heat Sink (mm) Board Size (in inches) and Layers
None 0 No heat sink  
Low 100 25 x 25 x 5 JEDEC (4”X4”) with 2s2p
Medium 200 20 x 30 x 15  
High 400 50 x 50 x 25 10” x 10” with 10 Layers

Based on the above conditions, the table below provides a set of approximate values of percentage heat to heat sink. You can use these values to determine heat sink requirements.

Table 5.  % of Heat Generated in the FPGA Flowing into the Heat Sink Based on Boundary Conditions
% Heat to Heat Sink
  4" x 4" PCB with 2s2p 10" x 10" PCB with 10L
Airflow (lfm) 0 100 200 400 0 100 200 400
No heat sink * 5% 5% 10% 15% 5% 5% 5% 10%
25 x 25 x 5 heat sink 15% 30% 40% 50% 10% 20% 30% 40%
30 x 30 x 15 heat sink 40% 70% 80% 80% 30% 60% 70% 80%
50 x 50 x 25 heat sink 70% 80% 85% 90% 55% 75% 80% 80%
* % heat to heat sink for the No heat sink case simply means the amount of heat going through the top of the device. The remaining heat flows to the PCB. This value helps you determine whether a heat sink is needed for the device.

To design a heat sink that is optimally sized for the ambient conditions, air flow and PCB thermal conductivity, you should follow the steps detailed below.

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