Mini Thermal Analysis

Why You Need Early Thermal Analysis

Thermal analysis is the basis for other analyses such as component derating and MTBF calculations.

Early thermal and component derating analysis enables detection of overstressed components, resulting in optimal component size selection before PCB layout and component placement.

This enables the designer to perform design changes easily and cost-effectively.

With the information provided by the Mini-Thermal Analysis module, users can place warm components in a cooler area before layout, and define the proper cooling method and the airflow level.

This helps create an effective cooling system, and prevents overdesign or overstress.

fiXtress Mini Thermal Analysis

The fiXtress module estimates the board temperature increase based on self-heating, as fiXtress analyses are performed before PCB layout, and actual thermal data is still unknown.

This information is then used during the component derating analysis and MTBF prediction.

The module takes into account the exact power dissipation of each component, and estimates “The average temperature rise above the cold-plate temperature”, dT(oC).

The module takes the thermal data and package type of each relevant component, creates the thermal model and solves the equations resulting in dT(oC).

An example is presented in the following table:

The PCB cold-plate temperature is 71 T(oC),
fiXtress Mini Thermal Analysis tool calculated dT(oC) to be 6.4oC,
Generating average components temperature of (71+6.4) = 77.4oC.
Then, the tool adds for each component the internal component heat, e.g.
Tj=83.4oC for U3.

Mini Thermal Analysis

The following picture demonstrates the temperature map from a 3rd party thermal 3D simulation.
We can see that the results are similar.
We conclude that the Mini thermal analysis serves as a best practice to assess the PCB temperature before PCB layout and component placement.