Upscreening Commercial TVS Diodes For Avionics And Robust Environments Or Applications

The features and benefits of silicon TVS diodes are well understood by a broad user community of such devices. Microsemi Corporation is a world leader in the design, fabrication, and supply of these silicon-based transient protection devices in both hermetic and non-hermetic configurations. The company offers a broad portfolio of TVS devices at all power levels, including single devices which dissipate 40,000 watts (10/1000 µs) for high energy industrial and telecommunications applications, and 200,000 watts (10/40 µs) for avionics applications. Qualification test plans and reliability monitoring provided for all these products are in line with the best industry standard practices.

However, it is the position of Microsemi Corporation that such programs, while effective in reducing the incidence of device infant mortality in general, are inadequate when applied to larger TVS diodes relative to eliminating infant mortality during in-circuit operation, particularly as the junction area is expanded to withstand transient surges greater than 2,000 watts (10/1000 µs).

Microsemi's extensive screening history confirms that the anticipated yield loss from device infant mortality increases 1) with the power level of the TVS being specified and 2) with the complexity of the assembly required to meet the threat. Device mortality varies from nearly negligible for ESD protection to significant levels for lightning protection products. Table I reviews infant mortality causes in larger TVS devices.

SOURCE: Microsemi Corporation