Having a resistor network available that can take the heat — all the way up to a very hot 215°C — is a very good thing if you design jet engine control systems or oil down-hole extraction instrumentation or pressure sensors. For these designs and a lot more, the PRAHT four-resistor network from Vishay Intertechnology is really important.
That's why we gave the Vishay network a 2012 Product of the Year Award. It's an important device that gives engineers a TCR of 10 ppm/°C, a tolerance of ±0.1% or ±0.5%, and a ratio tolerance down to 0.05% — over that wide temperature range. There are quite a few designs that just can't live without this new network.
The network was designed and is produced at Vishay's facility in Nice, France. For a customer requirement, Vishay developed the PHT and RMKHT series thin-film high-temperature chip resistors in 2009. In 2011 they decided to offer the four-resistor chip array. The tight ratio tolerance between the four elements was a big draw for precision amplifier designs.
The PRAHT design team (L-R): Jean-Yves Rancurel, CAD manager, Didier Parmentier, CAD engineer, Rodolphe Cauro, R&D engineer, and Jerome Algrain, operational director.
When the team started the qualification of the new device and found tolerance matching and temperature coefficient tracking at 215°C was as good as at 140°C, they were amazed and really happy. Since then the product has had excellent market success and the designers went on further and have already pushed the limits to 250°C and even ran testing at 270°C. They assured me that new versions of this product will follow soon.
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