Introduction to Electrostatic Discharge (ESD) Risks and Suppression

2014-07-29 10:50:01 lipscall 309

Concern for the reliability of electronic products with respect to Electrostatic Discharge (ESD) continues to increase. At the IC chip foundry, the board assembly house, and in the field, ESD is a threat to the long-term functionality of the end product. 

Circuit Protection in the Production Environment
In the foundry and board assembly environments, two basic strategies are used. First, ESD protection structures are designed in o the ICs. Second, Electrostatic Discharge survivability is further enhanced by work place treatments like static-dissipative clothing and environmental modification (humidity/ionization control). When properly implemented, these treatments can ensure high yields with respect to Human Body Model (HBM), Machine Model (MM), and Charged Device Model (CDM) types of ESD events. 

Circuit Protection During End-Product Use
A circuit that survives HBM/MM/CDM events is not guaranteed to survive real-world ESD events, to which the end product (Tablet, smart phone, PC, etc.) will be subjected. User-generated ESD events, like those specified in the IEC 61000-4-2 test specification, are much more severe than those defined for foundry/assembly house environments. 

Because of the increased voltage and current stresses, user-generated ESD events can cause electrical upset to, or outright destruction of, the ICs. To enhance survivability of the IC to user-generated ESD, suppression products are typically used. These devices supplement the on-board ESD capabilities of ICs so that the end product can reliably function after exposure to severe Electrostatic Discharge events. 


Littelfuse ESD Suppressor Product selction and Application Expertise

To help the circuit designer best match a suppression solution to their circuit characteristics, Littelfuse offers a in-depth application support and a broad portfolio of ESD suppression products, including ceramic, silicon and polymeric technologies.

Since all applications and circuits are different, no one, single, transient voltage suppression technology can solve every problem. Some important transient voltage suppressor characteristics to consider (which vary by technology) include capacitance, leakage current, clamping voltage, and package outline. It is best to contact the Littelfuse application support representative in your region for guidance. 

Littelfuse recognizes that many applications present severe board-space limitations. To help minimize board-space usage, Littelfuse offers a wide selction of discrete and array devices that will serve most requirements