Precision Z-Foil molded surface-mount resistors with flexible terminations

Vishay Intertechnology launched precision Z-Foil molded surface-mount resistors, SMR1DZ and SMR3DZ with an instantaneous thermal stabilization time of < 1 second. The devices provide a 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., a PCR ("?R 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 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 new resistor concept developed by Vishay that utilizes Bulk Metal Foil and new fine photo-etching techniques, 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.

Some of the key features include:

1. The SMR1DZ and SMR3DZ offer a variety of screening options in accordance with MIL-PRF-55182.
2. The resistors feature flexible terminations to ensure minimal stress transference from the PCB due      to a difference in thermal coefficient of expansion (CTE).
3. The devices offer a wide resistance range of 5 O to 80 kO, and are not restricted to standard values.     Vishay can supply "as required" values (e.g., 7 kO vs. 7.5678 kO).
4. With these 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.
5. The SMR1DZ features a power rating of 250 mW at +70 °C, while the SMR3DZ offers a power rating      of 600 mW at +70 °C.
6. Both devices have a load-life stability of ±0.005 % for 2000 hours at 70 °C; a voltage coefficient of     <0.1 ppm/V; current noise less than -40 dB; and thermal EMF of 0.1 µv/°C.
7. They offer a fast rise time of 1.0 ns, effectively without ringing, and feature a non-inductive (<0.08 µH),      non-hot-spot design.
8. The SMR1DZ and SMR3DZ resistors offer the ESD immunity, withstanding electrostatic discharges      up to 25 kV.

Availability: Samples and production quantities of the new Z-Foil resistors are available now, with lead times of 5 weeks for larger orders.

Vishay can be found on the Internet at www.vishay.com