Understanding MSL Level Specifications

Electronics parts can be severely damaged by humidity. Here’s how MSL levels categorize those vulnerabilities for better electronics handling and manufacturing.

Published on January 25, 2023

Understanding MSL Level Specifications

MSL Levels: An Introduction 

It’s no surprise to anyone familiar with electronic devices that electricity and water don’t mix well. Anyone who’s ever dropped their favorite personal device in a puddle knows well that it doesn’t take long for water to completely ruin an electronic device. In electronics manufacturing, even the presence of too much humidity prior to and during the assembly of devices can lead to serious problems and defects, some of which are not obvious until much later. 

This is the reasoning for the creation of the IPC-M-109 standard. Created by IPC, a trade association (founded as the Institute of Printed Circuits), IPC’s simple mission statement is to help manufacturers build electronics better. The IPC-M-109 standard is one of many published by the IPC that are used widely in the electronics manufacturing industry. IPC standards include guidelines for PCB design and materials, manufacturing processes, inspection and assembly guidelines, and many other guiding principles that aim to achieve that simple goal: build electronics better. 

What is the IPC-M-109 Standard? 

The IPC-M-109 standard helps OEMs by assigning moisture sensitivity levels (MSLs) for electronic components. The longer a device such as a solder-down wireless module is exposed to ambient humidity, the greater the likelihood that it will suffer negative effects when reflowed. In particular, fine-pitch devices can suffer moisture absorption in the silicon that pops and breaks connections at reflow temperatures, a phenomenon known as the popcorn effect. 

If components are left out of their packaging and exposed to ambient temperature and humidity, they must be baked for a pre-defined amount of time to remove absorbed humidity. That amount of time is also part of the MSL definitions provided in IPC-M-109. Ezurio (formerly Laird Connectivity) provides definitions for all of our modules, giving OEMs critical guidance about how long our components can be exposed to ambient conditions. These levels vary by form factor, and are explained in detail in the following application note: 

Application Note – Moisture Sensitivity Level for Ezurio Products.

In short, the breakdown of MSL level for Ezurio products by product family is as follows: 

Solder-down ModulesMSL Level 472 hours of ambient exposure max
Exception: Lyra SeriesMSL Level 3168 hours of ambient exposure max
Plug-in modulesMSL Level 1Unlimited ambient exposure
Packaged productsNone listedNon-applicable

Our MSL Level application note lists all of our recommended MSL levels by product family with detailed lists of the product families and parts included. For more information, see our Application Note – Moisture Sensitivity Level for Ezurio Products.