LTspice plot of differential and common-mode noise, with conducted emissions limit line. Solving Emissions and Immunity Problems Using LTspiceĪfter reading this article you should be able to answer the following key questions:Ī) Is my system likely to pass EMC testing? Shall I keep an extra footprint for a common-mode inductor, a filter inductor, or a capacitor? After reading this article you should be able to use LTspice to plot differential and common-mode noise in your buck converter power design and show how the circuit passes or fails conducted emissions standard limits, as shown in Figure 1.įigure 1. Part 3: signal conditioning components and boosting immunity to external noise.Part 2: signal integrity and transient robustness on cable drive transceiver links.Part 1: power supply components and conducted emissions and immunity.
However, many of the components and EMC simulation techniques are not unique to MEMS solutions and can be used across a broad range of applications.
This is Part 1 of a series of three articles that provide EMC simulation models for an example sensor signal chain, with a MEMS vibration sensor at its core. This article series provides some guidelines and LTspice EMC circuit models that are simulated and well matched to real lab measurements. To be useful, an EMC simulation tool needs to be as accurate as possible. Spending a few hours simulating EMC failures and circuit fixes helps to avoid multiple lab test iterations and expensive hardware redesigns. With many of us working from home, and EMC lab costs at a premium (up to $2000 daily), accurate EMC simulation tools are even more useful. Usually, simulation focuses on the functional aspects of an electronic device however, a simple and open-source tool such as LTspice can also be used to simulate the EMC behavior of any device. This article provides open-source LTspice ® simulation circuits to answer key questions: (a) will my system pass EMC testing, or do I need to add mitigation techniques? and (b) how immune is my design to noise from the external environment? Why Should I Use LTspice for EMC Simulation?ĭesign for EMC should follow the product release schedule as closely as possible, but this is often not the case, as EMC problems and lab testing can delay product release for months. Meeting EMC compliance targets is often a complex task.
How to Get the Best Results Using LTspice for EMC Simulation-Part 1Īs technological innovations such as IoT connected devices and 5G connectivity become part of our everyday lives, so too does the need to regulate the electromagnetic emissions from these devices and quantify their immunity to EMI.