VPG enhances resistance range of Bulk Metal Z-Foil resistors

Posted By : Nat Bowers
VPG enhances resistance range of Bulk Metal Z-Foil resistors

Vishay Precision Group have revealed that it has extended the resistance range of its VFCP series of Bulk Metal Z-Foil ultra-high-precision flip chip resistors. Now featuring resistances down to 5 Ω, the VFCP series resistors also provide resistances up to 125 kΩ. Any conceivable ohmic value within this range, to six digits, is available with no additional cost or lead time effect.

Operating over a wide temperature range from -55°C to +125°C, the newly enhanced devices feature ultra-low TCR of ±0.05 ppm/°C nominal (0°C to +60°C) and ±0.2 ppm/°C typical (-55°C to +125°C, +25°C ref.). This extremely low TCR of over a wide temperature range makes them suitable for the high demands of cryogenic applications. Qualified as anti-sulfurated resistors for use in environments with high levels of contamination, the VFCP series resistors are ideal for use in many alternative energy, RTD, Li-ion battery, 4 mA to 20 mA current loops, and smart grid applications in which analog circuitry operates under severe environmental, thermal, and mechanical conditions. Designing and manufacturing equipment for these applications involves extreme challenges: precision resistors must be ultra-stable, ultra-reliable devices with an extremely low total error budgets.

Offering a load-life stability of ±0.005% at 70°C for 2,000 hours at rated power and ±0.01% at 70°C for 10,000 hours, the VFCP series is available in five chip sizes ranging from 0805 to 2512. With tight resistance tolerance to ±0.01%, the resistors also provide high power ratings up to 600 mW at +70°C and an excellent power coefficient (ΔR due to self-heating) of ±5 ppm at rated power. They feature one-side terminations to ensure secure contact during the manufacturing process and provide better strain relief to eliminate cracked substrates and board delamination. The one-side terminations also save up to 35% PCB space compared with a surface-mount chip with wraparound terminations.

Yuval Hernik, senior director of application engineering for VFR, comments: "Many designers use a resistor's TCR as a shorthand index to its relative level of precision. And while it is generally true that a better TCR does correspond to higher precision, this degree of precision does not maintain the same TCR/precision proportion across all technologies. For Bulk Metal Foil resistors, the stress/strain balance throughout the temperature and power application ranges ensures that none exceeds the elastic limit (Hooke's law) for any material used and that all performance criteria are repeatable and reliable."

Available with both lead (Pb)-free and tin/lead alloy terminal finishes, VFCP devices offer a rise time of 1.0 ns with effectively no ringing, a thermal stabilization time of <1 s (within 10 ppm of steady-state value), current noise of 0.010 µVrms per volt of applied voltage (< -40 dB), and a voltage coefficient of <0.1 ppm/V. Featuring a non-inductive (< 0.08 μH), non-capacitive design, the resistors are immune to extraordinary incidents such as radiation exposure and withstand ESD spikes to at least 25 kV.

Featuring lead times of five days for prototype samples and two days to six weeks for standard orders, the VFCP series Z-Foil resistors are available now for sampling and in production quantities.


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