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MALVERN, Pa. — July 20, 2011 — Vishay Precision Group, Inc. (NYSE: VPG) today announced that its Vishay Foil Resistors division (VFR) has released a new ultra-high-precision Foil surface-mount current sensing chip resistor with low TCR of ±2 ppm/°C from -55 °C to +125 °C, +25 °C ref., and tolerances to ±0.1% (0.01% and 0.05% are available). For high-power applications, the VCS1625P offers a power rating of 1 W at +70 °C and maximum 5 A current rating, and a four-terminal Kelvin configuration for increased accuracy.
The VCS1625P features a wide resistance range from 0.01 Ω to 10 Ω, with specific “as required” values within this range (e.g. 1.234 Ω vs. 1 Ω) available at no additional cost or delivery time. The resistor features a rise time of 1.0 ns, with effectively no ringing, short time overload of < 0.005% (50 ppm), current noise of 0.010 µVrms/V of applied voltage (< -40 dB), and a voltage coefficient of < 0.1 ppm/V. Offering the utmost in electrostatic discharge (ESD) immunity, the device withstands ESD to at least 25 kV, for increased reliability, and offers a non-inductive (< 0.08 μH), non-capacitive design. The VCS1625P is offered with tin/lead or lead (Pb)-free gold or tin termination options, and with additional temperature treatments (PMO) to extend the operating temperature from +150 °C to well above +200 °C. The design of the VCS1625P allows for designers to use only a single device to measure larger currents than previously possible by dissipating up to 1 W in the same 1625 size package.
The Bulk Metal® Foil technology of the VCS1625P provides a significant reduction of the resistive component’s sensitivity to ambient temperature variation (TCR) and to the “self-heating” effect caused by changing loads. These capabilities allow designers to guarantee a high degree of stability and accuracy in fixed-resistor applications. The resistor’s load-life stability at +70 °C at rated power is an order of magnitude better than typical current sensing resistors (0.015% after 2,000 hours versus 0.05% after 10,000 hours). The device’s improved stability makes it ideal for tightened-stability reference voltage and precision current sensing applications in forced-balance electronic scales, measurement instrumentation, bridge networks, motor controllers and medical and test equipment. In addition, the VCS1625P can be tested in accordance with EEE-INST-002 (MIL-PRF 55342) for military and space applications.
The resistor’s design results in a very low thermal EMF of 0.05 μV/°C typical, which is critical in precision applications. The VCS1625P’s all-welded construction is composed of a Bulk MetalFoil resistive element with plated copper terminations. The flat terminations make intimate contact with the resistive layer along the entire side of the resistive element, thereby minimizing temperature variations. In addition to the low thermal EMF compatibility of the device’s metals, the uniformity and thermal efficiency of the design minimize the temperature differential across the resistor, thereby assuring low thermal EMF generation at the terminations. This further reduces the thermal EMF voltage, or “battery effect,” exhibited by most current sensing or voltage reference resistors.
The device released today is characterized by extremely low excess noise when compared to other resistor technologies. Additionally, the current in adjacent current-carrying paths runs in opposing directions, cancelling the parasitic inductance of these paths. Also, path-to-path capacitances are connected in series, which has the effect of minimizing the parasitic capacitance of the resistor. The low-inductance/capacitance VCS1625P resistor is characterized by non-measurable peak-to-peak signal distortions.
Samples and production quantities of the VCS1625P are available now, with lead times of five working days for samples, and six weeks for standard orders.
About Vishay Foil Resistors
Vishay Foil Resistors is a division of Vishay Precision Group, producing the most precise and stable type of resistors available. The portfolio comprises products in a variety of resistor configurations and package types to meet the needs of a wide range of applications: discrete resistors and resistor networks in surface mount and through-hole (leaded) configurations; customized chip resistor networks; precision trimming potentiometers; and discrete chips for use in hybrid circuits. The foil resistors and current sensors are used in applications requiring a high degree of precision and stability, such as in medical testing equipment, high performance audio equipment, precision measuring instruments and aerospace and military applications.
About Vishay Precision Group
Vishay Precision Group (VPG) produces sensors based on precision resistive foil technology, and sensor-based systems. It provides vertically integrated products and solutions for multiple growing markets in the areas of stress, force, weight, pressure and current measurements. As a spin-off from Vishay Intertechnology, VPG’s decades-long track record encompasses innovations in foil precision resistors, current sensors, and strain gages, which have served as a foundation for VPG’s more recent expansion into strain gage instrumentation, load cells and transducers, weighing modules and complete systems for process control and on-board weighing. Vishay Precision Group may be found on the Internet at www.vishaypg.com.