/> The improved resistance stability of the CSM3637Z makes it an excellent choice for tightened-stability voltage division, precision current sensing, and pulse applications in switching and linear power supplies, power amplifiers, feedback circuits, measurement instrumentation, bridge networks, satellites and aerospace systems, and medical and test equipment. The device's stability can be further enhanced by post-manufacturing operations (PMO) that are uniquely applicable to Bulk Metal Foil Technology, such as temperature cycling, short-term overload, and accelerated load-life.

Traditional passive current sensors and shunts generate heat under power, which changes their resistance, and thus their voltage output. The CSM3637Z's low absolute TCR reduces errors due to temperature changes, thus reducing a major source of uncertainty in current measurement. Consider a typical current sense resistor with a TCR of 20 ppm/°C. While dissipating a power level that raises its temperature by 100 °C, it exhibits a 2000 ppm (0.2%) resistance change. That's a 0.2% error in the measured current flowing through the resistor. Moreover, the temperature rise is not linear with power dissipation, and the measured current has an additional non-linearity relative to the current flow through it. The only way to reduce this error is with a very low absolute TCR as in the CSM3637Z. Further, the CSM3637Z can withstand unconventional environmental conditions, including the extremely high temperatures and radiation-rich environments of down-hole oil exploration and well logging, or the deep-sea underwater repeaters in cross-ocean communications.

The CSM3637Z features a low thermal electromotive force (EMF) that is critical in many precision DC applications. The device's all-welded construction is composed of a Bulk Metal resistive element with welded copper terminations, plated for soldering. The terminations make true ohmic contact with the resistive layer along the entire side of the resistive element, thereby minimizing temperature variations. The resistor element is designed to dissipate power uniformly without creating hot spots, thereby minimizing parasitic contact resistance and contact resistance variation for a low thermal EMF of <3 µV/°C.

Featuring a four-terminal (Kelvin) design for precise and accurate current measurement, the CSM3637Z offers a power rating of 3 W for a resistance range of 3 mΩ to 10 mΩ and 2 W for 10 mΩ up to 50 mΩ. VFR foil resistors are not restricted to standard resistance values, and they can be supplied with as required values (e.g., 10.2345 mΩ vs. 10 mΩ) at no extra cost or delivery time. The device features a maximum current up to 31 A, very low inductance of 0.5 nH, excellent frequency response to 50 MHz, and short time overload of ±0.1% typical. The CSM3637Z's specifications are based on tests performed in accordance with methods prescribed by appropriate MIL-PRF standards (MIL-PRF-55342 and MIL-PRF-49465). Available in waffle-pack or tape-and-reel packaging, the resistor is available with lead (Pb)-free and tin/lead alloy terminations.

Designers often unnecessarily pay for tighter tolerances than required simply to accommodate the resistance stability shifts they know to be imminent in an application due to the large application-related changes in the components they selected. Selection of a high-stability component such as the CSM3637Z in these applications eliminates the need for shift allowance due to planned instability and allows initial tolerances to be looser than would be necessary with current-sensing resistors based on other technologies. Additionally, the overall system cost is often reduced by eliminating the necessity of additional compensating circuitry or temperature-controlling systems.