Vishay High-Precision Bulk Metal Foil and Z-Foil Resistors With TCR Down to ±0.2 ppm/°C, Tight Tolerance to ±0.01 %, and Nearly Immeasurable 1-ns Rise Time

The devices released today offer a broad resistance range of 5 Ω to 120 kΩ, a voltage coefficient of < 0.1 ppm/V, and a low current noise of < -42 dB. Like all Vishay Foil resistors, the VSH/Z and VSC/Z are not restricted to standard values, and can be supplied with “as required” values (e.g. 9.997 kΩ vs. 10 kΩ) at no extra cost or delivery time. The resistors feature a power rating of 300 mW at + 70 °C, with a maximum working voltage of 300 V.

While other resistor technologies can take several seconds or even minutes to achieve a steady-state thermal stabilization, the VSH/Z and VSC/Z have an almost instantaneous thermal stabilization time of < 1 second. Built to handle unconventional environmental conditions with minimal drift, these are the ultimate resistors for analog applications. Their construction guarantees a high level of reliability, and provides high resistance to thermal shock, moisture, mechanical shock, and vibrations.

Typical applications for the resistors will include dc-to-dc converters, feedback circuits, and high-precision amplifiers in test and measurement instrumentation; laboratory, industrial, and medical systems; electron beam applications; commercial and military avionics; audio systems; and down-hole drilling instrumentation.

The devices are the result of a unique concept in resistor manufacturing. A proprietary Bulk Metal Foil element with known and controllable properties is applied to a special ceramic substrate. A resistive pattern is then photoetched by an ultra-fine technique developed by Vishay. The devices’ etched planar construction results in the extremely low and reproducible reactance needed for high-frequency and pulse applications.

In applications requiring precise and stable resistors, TCR needs to be low over the full temperature range of the application. Only Z-Foil resistors, such as the VSHZ and VSCZ, provide a very low absolute TCR that changes very little over the full temperature range of − 55 ° C to + 125 °C and beyond.

Vishay Foil resistors are uniquely enhanced by Post Manufacturing Operations (PMO) exercising after the manufacturing cycle is complete. Some of these exercises are a standard part of the manufacturing cycle and are only repeated during the PMO cycle to gain added stability or confidence in the product. The Foil resistor load-life curve shows an increase in resistance from the first load application, but flattens out to no change after 500 to 1000 hours of loading. This knee in the load-life curve can be removed by a special accelerated load-life operation performed by Vishay, resulting in a flat response immediately after installation. Other resistive devices show a continuous change when subjected to these same stresses and are driven out of tolerance. Contact Vishay Foil Engineering sales (Foil@vishay.com) for assistance in specifying the PMO routine to be used in your application.

The VSH/Z and VSC/Z resistors withstand electrostatic discharges up to 25 kV for increased reliability and offer a non-inductive (< 0.08 µH), non-capacitive design. The devices are available with lead (Pb)-free and tin/lead alloy terminations.

Samples and production quantities of the new resistors are available now, with lead times of 72 hours for samples, and four weeks for standard orders.