450-W TVS Diode Arrays Offer ESD Protection
February 12, 2013. Littelfuse Inc. has introduced the 450-W SD05 (unidirectional) and SD05C (bidirectional) Series general-purpose TVS (transient-voltage-suppression) diode arrays, which are designed to replace multilayer varistors (MLVs) for protecting electronic equipment from damage due to electrostatic discharge (ESD) and other transient events. Unlike ceramic devices, which have an inherent wear-out factor, SD05 and SD05C Series devices are made of silicon diodes, which allows them to absorb repetitive ESD strikes or surge transients safely without performance degradation.
The devices' low dynamic resistance (0.5 Ω for the SD05 and 0.6 Ω for the SD05C) provides up to a 50% reduction in clamping voltage when compared with competing technologies, and the devices can safely dissipate induced surge currents up to 30 A. Typical applications of these devices include buttons/keypads, switches, DC power ports, and various other low-speed I/Os in point-of-sale terminals, test equipment, medical equipment, desktop/notebook computers, servers, and computer peripherals.
Chad Marak, director of the Littelfuse TVS Diode Arrays product line, said the SD05 and SD05C can serve in medical, industrial, consumer, and computing applications, adding, “They allow designers to add ESD and/or surge protection around the printed circuit board (PCB) as needed. Their compact SOD-323 package fits right into the footprint of an 0805 MLV, allowing manufacturers to replace them in their designs with a SD05 or SD05C device without requiring a PCB or solder pad change.”
The SD05 and SD05C Series offer protection against lightning transients in accordance with IEC61000-4-5, (30 A, tp = 8/20 μs) and ESD in accordance with IEC61000-4-2 (±30-kV contact discharge). Leakage is 1 µA max. The vendor reports that the devices provide up to a 50% reduction in clamping voltage compared with competing technologies and up to a 97% decrease in leakage current compared to previous technologies, thereby increasing battery life.