GaN Talk a blog dedicated to crushing silicon
How to Use the GaN FET Thermal Calculator to Boost Reliability and Shorten Time-To-Market in Power Electronics System Designs

How to Use the GaN FET Thermal Calculator to Boost Reliability and Shorten Time-To-Market in Power Electronics System Designs

May 07, 2022

When “displacement” technologies such as EPC’s GaN power FETs and ICs are introduced and new levels of performance are possible, modeling your design offers comfort and insight to your circuits’ capabilities and needs. This blog post discussed the latest addition to the “EPC GaN Power Bench, our on-line modeling tool library, EPC’s GaN FET Thermal Calculator

Gallium nitride (GaN) power devices offer a more efficient alternative to the aging silicon based MOSFET and ICs.  In a nutshell, GaN devices are smaller, they switch faster and have lower on-resistance resulting in greater efficiency than their silicon counterparts. Even with their higher efficiency and lower losses, all electronic devices dissipate some power as heat. EPC’s GaN FET Thermal Calculator helps your design capture the full performance value of a GaN power circuit and mitigate the design challenges before committing to a layout.

The thermal calculator provides quick estimates for the thermal performance parameters of PCB-mounted GaN devices subject to both board-side cooling through forced convection, and backside cooling through a thermal solution consisting of a heat spreader and heatsink. The model accounts for the PCB construction (size, stack-up and via density), die sizes, power losses, TIM materials and heat sink solution.

The GaN FET Thermal Calculator has a comprehensive user guide to describe the tool and starts with a short paragraph giving a brief description for each option. You will start with a generic schematic and a prompt to use the different panels in the app to set up the thermal system to reflect your design environment. This tool gives a designer the capability to model the additions of thermal management components such as heat spreaders, thermal interface materials (TIM) and heat sinks to give insights to the impact of including these options.  Figure 1 shows an example of the heatsink inputs available in the model.  It is also possible to model design enhancements such as paralleling devices to determine the most efficient path for your product.

Figure 1: Example heatsink calculator inputs from the GaN FET Thermal Calculator

The result of using the GaN FET Thermal Calculator is that after defining all the input parameters for the thermal system, the results are updated, and the operating temperature and temperature rise from ambient is reported for each device. A detailed report is also generated and can be expanded to read the estimated thermal resistances of the circuit model.

A video that further explain EPC’s Thermal Model Calculator is also available:

Online Thermal Calculator - Introductory Video

The GaN FET thermal calculator serves as a quick thermal tool for electrical designers to estimate the thermal capabilities of a GaN device and to assess the effectiveness of thermal management strategies. Added features allow additional analysis and results comparison. The calculator is very effective tool used in early design stages for estimating thermal requirements, sizing and comparing thermal solutions, and assessing the thermal feasibility of circuit board designs.

The GaN Power Bench also has an on-line selection tool for DC-DC Converters and a cross reference tool to complement the device model libraries and demonstration boards available to help optimize design from concept to conclusion.  For additional assistance with these tools or to discuss the specifics of your design, Ask a GaN Expert