LTspice Lesson 6: How to do Thermal Simulations in LTspice?

Blocks Covered:

All electronics components generate heat. One of the system designers job is to figure out how to get rid of this heat efficiency and cheaply either designing an active or passive or both active and passive cooling solution. Passive cooling might be just a heat sink attached to a hot device on the board. In this lesson, we will focus on how to simulate thermal performance if your heat generating device such as MOSFET is within its maximum junction temperature.

The IC devices consist of at-least one die which is a main source of heat due to power consumed. In the thermal design, we need to make sure we stay within the maximum junction temperature specified by the manufacture. The main goal of this simulation is get the junction temperature. Now there is no direct access to measure the junction temperature but only to measure case temperature, but given the thermal resistance, one can calculate the junction temperature using simple ohm law applied to heat transfer. We will go over the basic of thermal ohm law and how to create a simple model and verify the model using LTspice SOAterm blocks.

To be continued


About ExploreSilicon

My name is Kashif. I live in the heart of silicon valley and have been living here for a very long time. My passion is engineering, technology and traveling. My email is Please feel free to contact if you have any suggestion or comments on any of my posts.
This entry was posted in LTspice for EE students and tagged , . Bookmark the permalink.

1 Response to LTspice Lesson 6: How to do Thermal Simulations in LTspice?

  1. Raymond Coulson says:

    Great lesson, I wonder if you can teach us how to build my own model from experiment data. I measure static and dynamic response of a sensor and try to put it to my spice simulation, but this sensor is quite unlinear, my attempt to model it with component already in LTSpice but can’t reach accuracy I need.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s