Vishay Foil Resistors announced that it has enhanced its SMR1DZ and SMR3DZ ultra-high-precision Z-Foil molded surface-mount resistors with an almost instantaneous thermal stabilization time of < 1 second. The devices provide a low typical TCR of ±0.05 ppm/°C from 0°C to +60°C, +25°C Ref, and ±0.2 ppm/°C from −55°C to +125°C, +25°C Ref., an excellent PCR (“ΔR due to self-heating”) of ±5 ppm at rated power, tolerances to ±0.01%, load-life stability of 0.005% (50 ppm) at rated power for 2000 hours at ±70°C, and end-of-life tolerance to less than 0.1%. This superior performance is built into every unit, and does not rely on culling or other artificial means for uniform excellence.
The SMRxDZ series is based on a resistor concept developed by Vishay that utilizes proprietary Bulk Metal® Foil and fine photo-etching techniques created by the company, so that the conductor can be considered a flat wire. Because the metals used are not drawn, wound, or mistreated in any way during the manufacturing process, the SMRxDZ series maintains all its design, physical, and electrical characteristics. These factors are both measurable and predictable before, during, and after manufacturing.
The SMR1DZ and SMR3DZ offer a variety of screening options in accordance with MIL-PRF-55182. The enhanced resistors feature flexible terminations to ensure minimal stress transference from the PCB due to a difference in thermal coefficient of expansion (CTE). The devices offer a wide resistance range of 5 Ω to 80 kΩ, and like all Vishay Foil resistors, are not restricted to standard values. Vishay can supply “as required” values (e.g., 7 kΩ vs. 7.5678 kΩ) at no extra cost or delivery time.