Circuit protection is used in virtually every electrical or electronic device, protecting not only the device, but people, businesses, and reputations. These devices guard sensitive electronics against damage from overcurrent, overvoltage, ESD, surges, and other destructive events, serving as an intentional weak link resulting in controlled rather than catastrophic failure.
Circuit protection should be specified as soon as the chipset or other fundamental components have been determined, allowing for proper protection devices to be selected and integrated in the design prior to starting PCB layout. Delaying this critical consideration can result in redoing the layout and less optimal device selection and location leading to a less reliable and potentially unsafe design.
Beyond standard cartridge fuses protection devices include PTCs, GDTs, MOVs, ESD suppressors, TVS diodes and arrays, Thyristors, SIDACtors, and LED protectors, each with unique properties, applications, or benefits. These devices should not be thought of as simple commodities to be selected without engineering expertise. Littelfuse provides resources to help designers determine the appropriate protection devices for their specific applications.
The Electrostatic Discharge Suppression Design Guide provides an overview of ESD suppression technologies and requirements, types of damage that can occur, as well as design considerations. The guide helps design engineers determine the appropriate suppression technologies for the application with guidance for different data rates and protocols and provides example protection topologies for various types of ports.
The Fuseology Application Guide presents 11 critical factors , going beyond normal operating current and voltage to include ambient temperature, overload current conditions, maximum fault current, pulse conditions, physical constraints, required agency approvals, fuse and fuseholder features, and application testing and verification. By considering these factors, designers will be able to quickly and easily determine the correct fuse.
iDesign is the Littelfuse online design and product selection platform. The Fuse Design and Selection Tool incorporates the calculations and requirements set forth in the Fuseology Application Guide, providing users with an intuitive interface for selecting the optimal fuse. The ESD Selection Tool helps designers select from Littelfuse’s ESD suppression products and run simulations to compare system ESD levels, identifying the best device for their application. With iDesign, the user provides input at each step with the result being a list of suggested devices based on the input for that design, allowing designers to quickly select a device suited to their application.
For more information on these and other circuit protection resources, visit Speed2Design.com.