Vishay Releases High-Precision CECC-Qualified Bulk Metal Foil Resistors

The RS92N, RS92NA, and AN resistors are qualified to CECC, the standard for AMS applications requiring long-term stability and high reliability. The resistors’ ability to retain their initial value through temperature change, load application, frequency shift, and short-time overload is unmatched in the industry. Designers can expect these devices to display parts-per-million changes in service, as opposed to percentage changes that occur with thick film, thin film, and wirewound resistors.

In addition to their low absolute TCR, tight tolerance, and excellent load-life stability values, the devices released today feature thermal EMF of < 0.1 µV/°C; a voltage coefficient of < 0.1 ppm/V; and current noise < - 40 dB. The AN offers a broad resistance range of 80.6 Ω to 92 kΩ, while the RS92N and RS92NA offer resistance values to 120 kΩ. Vishay Foil resistors are not restricted to standard values, and Vishay can supply “as required” values (e.g. 90 kΩ vs. 90.123 kΩ) at no extra cost or delivery time.

The resistors feature a power rating of 0.5 W at + 70 °C and 0.25 W at + 125 °C. Each device measures 2.5 mm by 7.5 mm, with a height of 8.0 mm, and typically weighs 0.6 grams. The RS92NA offers 3.81-mm lead spacing, while the RS92N and AN offer 5.08-mm lead spacing.

Offering the utmost in ESD immunity, the resistors withstand electrostatic discharges up to 25 kV, for increased reliability, and offer a non-inductive (< 0.08 µH), non-capacitive design. While other resistor technologies can take several seconds or even minutes to achieve a steady-state thermal stabilization, the RS92N, RS92NA, and AN devices have an almost instantaneous thermal stabilization time of < 1 second, and a nearly immeasurable 1.0-ns rise time, effectively without ringing. The devices are available only with tin/lead alloy terminations.

The Foil element of the resistors consists of a special alloy chosen for its electrical, mechanical, and thermal characteristics. It is set on the substrate through a unique and proprietary process that does not subject the devices to the metallurgical changes that occur during the winding of wire, or during the evaporative process used in other forms of precision resistors. Each step of the manufacturing process is rigidly controlled, with extensive quality control ensuring that the alloy is kept in its pure state. Analog circuitry frequently depends on the stability of the resistor complement, making Bulk Metal Foil resistors uniquely suited to analog applications.

Typical applications for the resistors include dc-to-dc converters, feedback circuits, and precision amplifiers in test and measurement instrumentation, medical systems, satellites and aerospace systems, commercial and military avionics, weapons systems, and high-temperature systems including down-hole drilling.