VPG – Surface-mount foil resistors SMR1DZ and SMR3DZ feature almost instantaneous thermal stabilization (VPG SMRXDZ series)

Now available from VPG’s VFR division, SMR1DZ and SMR3DZ ultra-high-precision Z-Foil moulded surface-mount resistors now feature an almost instantaneous thermal stabilization time of <1 second.

The devices provide a low typical TCR of ±0.05ppm/C from 0C to +60C, +25C Ref, and ±0.2ppm/C from -55C to +125C, +25C Ref., an excellent PCR (∆R due to self heating) of ±5ppm at rated power, tolerances to ±0.01%, load-life stability of 0.005% (50ppm) at rated power for 2000 hours at ±70C, 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, says the company.

The SMRXDZ series is based on a new resistor concept developed by VFR that utilizes a proprietary Bulk Metal Foil and new 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 5ohm to 80kohm, and like all VFR Foil resistors, are not restricted to standard values. VFR can supply 'as required' values (e.g. 7kohm vs. 7.5678kohm) at no extra cost or delivery time.

With VFR Bulk Metal Foil resistors, only a minimal shift in resistance value will occur during its entire lifetime. Most of this shift takes place during the first few hundred hours of operation, and virtually no change is noted thereafter. The SMR1DZ features a power rating of 250mW at +70C, while the SMR3DZ offers a power rating of 600mW at +70C. Both devices have a load-life stability of ±0.005% for 2000 hours at 70C; a low voltage coefficient of <0.1PPM/V; current noise less than -40dB; and low thermal EMF of 0.1µv/C. They offer a fast rise time of 1ns, effectively without ringing, and feature a non-inductive (<0.08μH), non-hot-spot design.

The level of the voltage produced in electronic discharge (ESD) and static electricity depends on a number of factors, such as the affinity of the two bodies and the air humidity, and can reach over 25kV. The SMR1DZ and SMR3DZ resistors offer the utmost in ESD immunity, withstanding electrostatic discharges up to 25kV, for increased reliability.

The stability problems associated with analog circuits are notably pervasive, but knowledgeable selection of a few high-quality resistors, networks, or trimming potentiometers in critical locations can greatly improve circuit performance, long-term applications-related performance, as well as the designer’s peace-of-mind. Additionally, overall system cost is often reduced when a knowledgeable designer concentrates costs in a few exceptionally stable components whose proven minimal-deviation load and environmental stability can often eliminate the necessity of additional compensating circuitry or temperature-controlling systems. The SMRXDZ series with Z-Foil technology offer a good example of this principle, says the company.

Purchase Now from one of the Distributors below

Digi-Key

SMR1DZ

SMR3DZ

Farnell

SMR1DZ

SMR3DZ

Mouser

SMR1DZ

SMR3DZ