Metal Foil Resistors feature hermetically sealed design.

Press Release Summary:

Approved as reference resistors for metrology, laboratory, instrumentation, and industrial applications, H and HZ Series oil-filled Bulk Metal® Foil Resistors feature tolerances of 0.001% at 10 ppm, resistance range of 5 W to 1.84 MW, and rise time of less than 1 ns. Maximum TCR ranges from ±2 ppm/°C for H series to ±0.2 ppm/°C for Z-Foil HZ series. In both series, resistive element is mounted on PCB board to which axial leads are anchored.

Original Press Release:

Vishay's New Generation of Hermetically Sealed, Ultra-High-Precision Bulk Metal® Foil Resistors Features TCR From ± 0.2 ppm/°C, Tolerance of ± 0.001 % (10 ppm), and Load-Life Stability of ± 0.002 % (20 ppm) at + 25 °C for 2000 Hours at Rated Power

Secondary-Standard Devices Based on Z-Foil Technology Approved as Reference Resistors by the World Institute of Standards for Metrology, Laboratory, Instrumentation, and Industrial Applications

MALVERN, Pa. - Vishay Intertechnology, Inc. (NYSE: VSH) today announced two new series of secondary-standard, hermetically sealed, oil-filled Bulk Metal® Foil resistors that set new industry benchmarks for precision, stability, and speed. The new H and HZ series feature tolerances of 0.001 % (10 ppm), a resistance range of 5 W to 1.84 MW, shelf-life stability of 2 ppm (±0.0002 %) for at least 6 years (unaffected by humidity), and a rise time of < 1 ns. Maximum TCR ranges from ± 2 ppm/°C for the H series to ± 0.2 ppm/°C for the Z-Foil HZ series.

Vishay's H and HZ products offer an immediate answer to many challenging resistor applications previously thought to be unsolvable, including resistance standards, feedback devices for operational amplifiers, precision voltage dividers, meter multipliers, precision bridge resistors, and decade voltage dividers. As a result, the devices open entirely new areas of design where the use of resistors had not been considered.

In both "H" family product series, the resistive element is mounted on a PCB board to which axial leads are anchored. The electrical connection between the resistive element and the leads is provided through a special low-stress construction. After the assembly is inserted into a tinned brass shell, moisture is removed from inside the package using a proprietary process, and the unit is oil-filled and solder-sealed to permit uniform heat dissipation and minimize the effects of extreme environments. The hermetic sealing eliminates the ingress of moisture and oxygen, while the oil acts as a thermal conductor. By combining these techniques with its Bulk Metal Foil technology, Vishay has created in its "H" family products the most precise and stable resistors available.

With their extremely tight specifications, these devices are virtually secondary standards that can be carried in sets for daily or periodic calibration of factory measurement equipment. "H" family devices are also available with laboratory- and metrology-level precision and long-term stability with additional in-house oriented processes such as chip stabilization, special TCR plotting, additional treatments for ultra-stability, and special post manufacturing operations (PMO), such as temperature cycling, short-time overload, and accelerated load life, which are uniquely applicable to Bulk Metal Foil resistors.

Special construction allows the devices' copper leads to pass through the seal to the outside of the enclosure. This positions the more malleable solder-coated copper leads on the outside of the package and minimizes the thermal EMF at the internal termination-to-resistor junction assembly.

With the H and HZ series resistors, only a minimal shift in resistance value will occur during their entire lifetime. Most of the shift takes place during the first few hundred hours of operation and virtually no change is noted thereafter. This change can be eliminated with additional PMO as mentioned above. Please contact our engineers to provide the suitable PMO profile for your application.

"H" family devices feature a electrostatic discharge protection up to 25 kV, a rise time of 1 ns, with essentially no ringing, current noise of < - 40 dB, thermal EMF of 0.05 µV/°C typical, and a voltage coefficient of < 0.1 ppm/V. Note that Vishay Foil resistors are not restricted to standard values, and specific "as required" values (e.g. 1.234 kW vs. 1 kW) can be supplied at no extra cost or delivery time. Key specifications for the two "H" family options are summarized in the following table:

Device Specification Table:
Specification      H Series     HZ Series (Z-Foil)
Typical TCR ± 2 ppm ± 0.2 ppm
Standard resistance range
(higher/lower values available) 5 ohm to 1.84 Mohm 5 ohm to 1.1 Mohm
Load life stability ± 0.002 % ΔR ± 0.002 % ΔR
(25°C for 2000 h at rated power) (25°C for 2000 h at rated power)

Samples and production quantities of the H and HZ resistors are available now with sample lead times from ten working days and standard orders from five weeks.
Vishay Intertechnology, Inc., a Fortune 1,000 Company listed on the NYSE (VSH), is one of the world's largest manufacturers of discrete semiconductors (diodes, rectifiers, transistors, and optoelectronics and selected ICs) and passive electronic components (resistors, capacitors, inductors, sensors, and transducers). These components are used in virtually all types of electronic devices and equipment, in the industrial, computing, automotive, consumer, telecommunications, military, aerospace, and medical markets. Its product innovations, successful acquisition strategy, and ability to provide "one-stop shop" service have made Vishay a global industry leader. Vishay can be found on the Internet at

Bulk Metal is a registered trademark of Vishay Intertechnology, Inc.

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