ESD Standard Vis a Vis IoT applications

April 25, 2016 // By Jim Colby
Looking at the most common threat to IoT, electro static discharges, and how to deflect them.

The home of the future – smart appliances that help you track your fresh food purchases as well as advising what and how to cook your meals; smart lighting systems that sense the ambient light conditions and adjust brightness accordingly or shift their color palette to change the mood; smart climate controls that ”learn“ the habits of the residents to most efficiently use energy to heat or cool; smart gateways that manage data, entertainment and communication; smart wearables and clothing that provide feedback on fitness activity and health parameters and that track those metrics to allow an individual to adjust their behavior to get positive health benefits; smart vehicles and traffic systems that improve traffic flow patterns and that make road travel safer.

Sounds pretty good!  This vision of a future with a fully functional Internet of Things is quite bright with many new capabilities that allow individuals to take more control of their surroundings with respect to efficiency, enjoyment and even for better health.  Similarly, smart factories will improve their owners‘ ability to control the process, quality and cost more effectively through coordinated manufacturing, measuring and analyzing systems.

What do all these systems have in common, and more importantly, what does it take for them to be considered ”smart“?  Communications!  The ability to receive and transmit information is crucial to systems being considered for inclusion in modern, smart systems.  But, these information paths also provide an entry way for electrical threats to enter the system and damage it.  Specifically, the most common threat is ElectroStatic Discharge (ESD).  Any time that a cable makes contact with a connector, or a person makes contact with an electronic system, there is a possibility of electrical charge transfer.

For system designers, this provides a threat to the integrity and reliabilty of their piece of the Internet of Things.   As the charge spreads out on the surface of the application, some or most of the charge can make its way through the connector (or other interface) and into the sensitive circuitry inside.  In order to help system designers understand how to harden their product against ESD, a number of Standards have been developed, with the goal of ensuring the reliability of the integrated circuits, and thus, the application itself.

These Standards are designed to help at different levels of the electronic ecosystem:

  • Human Body Model:It is based on a model of discharging a 100pF capacitor through a 1,500Ω resistor.Test voltages of 500V to 1,000V are typically used.This test is performed on integrated circuits to ensure they can survive the wafer fab and assembly processes.

ESD Standard Human Body Model; also known as HBM; in wafer fabs and back-end assembly environments.