VPG – Ultra high- Z-Foil resistor for demanding applications (VPR220Z)

A new ultra high-precision Z-Foil resistor, the VPR220Z, has been introduced by Vishay Precision. The device provides an industrial-grade absolute TCR of ±0.05ppm/C from 0C to +60C and ±0.2ppm/C from -55C to +125C, +25C ref., a power rating up to 8W at +25C per MIL-PRF-39009 (1.5W in free air), an ‘excellent’ power coefficient (?R due to self heating) of ±5ppm at rated power, and a tolerance of ±0.01%, says the company.

The VPR220Z resistor is built on proprietary Z-Foil technology, which provides a significant reduction of the resistive component’s sensitivity to ambient temperature variations (TCR) and applied power changes (PCR). Z-Foil improves stability by an order of magnitude compared to any other resistor technology, allowing designers to ‘guarantee’ a high degree of accuracy in fixed-resistor applications.

The device allows designers to achieve much better performance by combining a range of ultra high-precision specifications in a single device. These specifications include a load-life stability of ±0.005% (50ppm) for 2000 hours at +25C; a low voltage coefficient of <0.1PPM/V; current noise of <-42dB; and thermal EMF of 0.05µV/C. The resistor features a non-inductive (<0.08µH), non-capacitive design, and a 4-Kelvin connection for increased accuracy.

While other resistor technologies can take several seconds or even minutes to achieve a steady state thermal stabilization, the VPR220Z has an almost instantaneous thermal stabilization time of <1 second, and a nearly immeasurable 1ns rise time without ringing. Optimized for military and space applications according to EEE-INST-002 screening, the resistor is built to handle unconventional environmental conditions with minimal drift.

Offering the ‘utmost’ in ESD immunity, the device withstands electrostatic discharges exceeding 25kV, for increased reliability. Within a resistance range of 5ohm to 10kohm, any value at any tolerance is available through calibration at no additional cost. Featuring the TO-220 package, the VPR220Z is offered with lead (Pb)-free and tin/lead alloy finishes, and is available in a surface-mount version, the VPR220SZ.

Typical applications include DC-DC converters, precision current sensing, feedback circuits, and precision amplifiers in test and measurement instrumentation, medical systems, satellites and aerospace systems, commercial and military avionics, and weapons systems, says the company