Oil-Filled Device Offers Unique Construction to Minimize the Effects of Stress Factors and Humidity
MALVERN, Pa. — Sept. 11, 2009 —Vishay Intertechnology, Inc. (NYSE: VSH) today announced the VHP100
, a new hermetically sealed ultra-high-precision Bulk Metal® Foil resistor with such a low temperature coefficient of resistance (TCR) that a new definition, “window,” has been introduced by Vishay. The window definition requires that the absolute resistance remain within the stated window over the temperature range specified.
The resistance of the VHP100
resistor stays within a 60-ppm window (0.3 ppm/°C maximum) over the entire military temperature range of - 55 °C to + 125 °C. This means that the difference between a resistor's maximum resistance value and its minimum resistance value shall not deviate by more than 60 ppm total over the entire military temperature range. This also means that all VHP100
resistors ever built will automatically maintain maximum temperature-related ratios of 120 ppm (0.012 %) over the entire temperature range regardless of whether the resistors are all at different temperatures and whether the different temperatures are caused by environmental temperature variations, locally different heat generated by adjacent power components, or even self-heating in power dissipation. A window of 10 ppm is available for the laboratory instrument range of + 15 °C to + 45 °C.
In addition to its low TCR, the VHP100
provides tight tolerances to ± 0.005 % (50 ppm) and a load-life stability of ± 0.005 % (50 ppm) typical for 2000 hours at + 70 °C and 0.3 W. An even tighter tolerance to ± 0.001 % (10 ppm) is available on request.
Representing a metrology and secondary standard resistor breakthrough, the new VHP100
features a unique construction that minimizes the effects of stress factors, making it an excellent choice for the most demanding instrumentation and laboratory applications.
The ability of the VHP100
to minimize changes in resistance when the resistor is subjected to stress factors ensures ultra-high performance for tight metrology specifications. As applications requiring this level of performance also require immunity to humidity, the device features a hermetically sealed metal and glass enclosure to protect the resistive element, and is oil filled to improve the thermal dissipation path to the outside.
The resistor offers a broad resistance range of 100 Ω to 150 kΩ and a shelf-life stability of ± 2 ppm typical through at least 6 years, which is essentially the metallurgical stability of the alloy itself. Vishay Foil resistors are not restricted to standard values, and can be supplied with “as required” values (e.g. 1.2345 kΩ vs. 1 kΩ) at no extra cost or delivery time.
While other resistor technologies can take several seconds or even minutes to achieve a steady-state thermal stabilization, the VHP100
utilizes a unique manufacturing process that results in an almost instantaneous thermal stabilization time of < 1 second, and a nearly immeasurable 1.0-ns rise time, effectively without ringing.
The stability of the VHP100
resistor can be further enhanced by post-manufacturing operations (PMO), such as temperature cycling, short-time overload, and accelerated load life which are uniquely applicable to Bulk Metal Foil Resistors.
With the VHP100
, only a minimal shift in resistance value will occur during its entire lifetime. Most of this shift takes place during the first few hundred hours of operation, and virtually no change is noted thereafter. The overall solution cost is thus lowered, since the very high stability of the VHP100
allows designers to eliminate other passive and semiconductor components that would otherwise be needed to compensate for the lower stability provided by typical resistors.
In addition to its excellent stability characteristics, the VHP100
withstands electrostatic discharges up to 25 kV for increased reliability and offers a non-inductive (< 0.08 μH), non-capacitive design. The VHP100
offers a current noise of 0.010 μV (RMS) per volt of applied voltage (< - 40 dB), thermal EMF of 0.05 μV/°C typical, and a low voltage coefficient of < 0.1 ppm/V
Samples and production orders of the VHP100
are available now, with lead times from five days for samples and four weeks for production quantities.
Vishay Precision Group Inc. has ceased to be a subsidiary of Vishay Intertechnology Inc. and is an independent publicly owned company.