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At Ozen Engineering, we like to discuss various engineering problems and modeling techniques to solve these issues. Today, we will focus on a specific ANSYS tool called iSPEC. This specialized software predicts the thermal field and cooling solutions for IC packages, printed circuit boards, and complete electronic systems.
Introduction to iSPEC
iSPEC includes numerous macros, one of which is particularly interesting and will be the focus of this video. This macro automatically builds and executes a JDEK test environment. Within this test bed, we place an IC thermal package and calculate the thermal resistance from the IC package to the case, known as theta JC, and from the IC to the board, known as theta JB.
Using ANSYS iSPEC 2024 R1
- Open the latest version of ANSYS iSPEC 2024 R1.
- Click on the library to explore the wide range of pre-existing components such as fans, filters, and heat sinks.
- Expand the packages section to view dozens of different IC packages.
- Select one of the larger packages and double-click to place it on the canvas.
- Auto scale the cabinet to wrap around the geometry and orient it to the home position for a closer view.
Preparing for the Macro
To prepare for running the macro, follow these steps:
- Identify the surface area in the Z and X directions, which is a 4 cm by 4 cm square.
- Right-click on the component to edit or double-click to view basic information.
- Increase the priority to 20 to ensure the component receives the highest priority during meshing.
- Turn on the die visibility, which is at the top gray level facing the maximum Y direction.
- Set the power dissipation of the die to 10 watts and update the settings.
Running the Macro
- Navigate to the macros section and select the modeling macro under IC packages named extract JB and JC.
- Choose to perform thermal characterization for both JC and JB.
- Set the package top side to max Y, ambient temperature to 20°C, and input the top surface area as 4 cm by 4 cm.
- Use the default high heat transfer coefficient for the top wall.
- For theta JB, choose the default JDEK 2S2P standard board and hit accept.
Results
The model will automatically set up and start running. The JC calculation is performed first, followed by the JB calculation. This process takes less than 5 minutes.
After completion, the results for theta JC and theta JB are displayed in degrees centigrade per watt. The solver runs in the background, showing convergence history and the calculated values.
Note: At Ozen Engineering, we ensure precision and accuracy in all our calculations.
Welcome to the OZON Engineering YouTube channel. Here we like to talk about different engineering problems and modeling techniques to solve these problems. Today I'd like to talk about a particular ANSYS tool: iSPEC.
It's a specialized software that predicts the thermal field and cooling solutions for IC packages, printed circuit boards, and complete electronic systems. iSPEC also comes with numerous macros, and one of them is particularly interesting.
It is a macro that automatically builds and executes a JDEK test environment. In this test bed, we place an IC thermal package and calculate the thermal resistance from the IC package to the case (Theta JC) and from the IC to the board (Theta JB).
For this purpose, I have opened up our latest version of ANSYS iSPEC 2024 R 1. The first thing I do is click on Library and select from the wide library of pre-existing components, such as fans, filters, heat sinks, and packages.
I will pick one of the larger packages, and when I double click on it, it essentially places it in our canvas. I then auto-scale our cabinet to wrap around our geometry, go to Orient, and click Home Position, which zooms in automatically. Now we can see our IC package and the environment around it.
To prepare for this macro to run, I need to do a few things. First, I need the surface area, which is in the Z and X direction. If I look at X Start and X End, I see a 4 centimeter by 4 centimeter square. We will use this as the area value in the script.
I right-click on our component and edit it to increase the priority to 20, ensuring our component gets the highest priority during the meshing stage. Next, I go to Macros, select the modeling macro under IC Packages, and click Extract JB and JC.
This brings up a new window, where I want to do thermal characterization for JC and JB, both of them. I select the package top side, as we decided was max Y, because the die is at the max Y location.
The ambient temperature is 20 degrees C, and the package type is the top surface area, which is 4 centimeters by 4 centimeters (about this much in square meters). I will use the default high heat transfer coefficient on the top wall for Theta JC and Theta JB.
The model will automatically start setting up and run. Once done, we have our Theta JC and Theta JB solution. The smaller window on the left side tells us the Theta JC and Theta JB values in degrees centigrade per watt. Please keep in mind that at all Z, we have a 0 rappelling.
