Bulk Metal Foil and Z-Foil Ultra-High-Precision Voltage Divider Resistors from Vishay

All Foil devices released today offer a low typical TCR of ± 2 ppm/°C from - 55 °C to + 125 °C, + 25 °C ref., while the Z-Foil devices feature TCR of ± 0.05 ppm/°C typical from 0 °C to + 60 °C and ± 0.2 ppm/°C typical from - 55 °C to + 125 °C, + 25 °C ref. The Z-Foil resistors provide PCR tracking (“ΔR due to self heating”) of ±5 ppm at rated power.



The devices’ low TCR is combined with tight tolerances and excellent load-life stability values for precision instrumentation amplifiers, bridge networks, and differential amplifiers in high-end medical, military, aerospace, automatic test, and down-hole drilling equipment.



TCR



TCR tracking requires an absolute TCR of less than three times the tracking requirement. For example, TCR tracking of 2 ppm/°C requires the absolute TCR for the two resistors to be within 6 ppm/°C or better. TCR tracking is also a function of applied power (Joule effect, or PCR). The lower the absolute TCR, the lower the PCR.



High-Power VFD244 and VFD244Z Voltage Divider Resistors



The new VFD244 and VFD244Z offer a high power rating up to 1 W at + 70 °C, divided proportionally between the two elements, over a working voltage of 350 V. The VFD244 features TCR tracking of 0.5 ppm/°C, while the VFD244Z provides tracking down to 0.1 ppm/°C. Both devices offer tolerance matching to ± 0.005 % (50 ppm), a load-life stability ratio of < 0.005 % (50 ppm) at +70 °C for 2000 hours at rated power, and a resistance range from 1Ω to 150 kΩ.



Conformally Coated VSH144 and VSH144Z Voltage Divider Resistors



The conformally coated VSH144 and VSH144Z feature tolerance matching to ± 0.01 % (100 ppm), a load-life stability ratio of < 0.01 % (100 ppm) at +70 °C for 2000 hours at rated power, and a resistance range from 100 Ω to 20 kΩ. The VSH144 offers TCR tracking to 0.5 ppm/°C, while the VSH144Z provides tracking down to 0.1 ppm/°C. Both devices feature a power rating of 0.2 W at 70 °C, divided proportionally between the two elements, over a maximum working voltage of 200 V.



Enhanced 300144/5 and 300144Z/5Z Voltage Divider Resistors



The enhanced 300144/5 and 300144Z/5Z offer TCR tracking to 0.5 ppm/°C and 0.1 ppm/°C, respectively. Both Foil and Z-Foil devices provide tolerance matching to ± 0.005 % (50 ppm), a load-life stability ratio of < 0.005 % (50 ppm) at +70 °C for 2000 hours at rated power, and a resistance range from 100 Ω to 20 kΩ. The devices offer a power rating of 0.2 W at 70 °C, divided proportionally between the two elements, over a maximum working voltage of 200 V. The 300145/Z provides a pair of 300144/Z elements back to back in a single molded package.



Summary



All new and enhanced divider resistors released today offer a low voltage coefficient of < 0.1 PPM/V, current noise of < -40 dB, and thermal EMF of 0.05 µV/°C typical. The resistors provide an almost immeasurable 1-ns rise time (effectively without ringing), and a non-inductive (< 0.08 µH), non-capacitive design. The devices are available with standard tin/lead or lead-free terminations. Offering the utmost in ESD immunity, the resistors withstand electrostatic discharges up to 25 kV, for increased reliability.



The resistors offer low excess noise and high linearity, or low voltage coefficient of resistance (VCR). These Bulk Metal Foil devices owe their low excess noise and high linearity to the type of material they’re made of: a metal, cold-rolled alloy foil with a thickness of several microns



While other resistor technologies can take several seconds or even minutes to achieve a steady-state thermal stabilization, Vishay’s Foil and Z-Foil resistors have an almost instantaneous thermal stabilization time of < 1 second (nominal value achieved within 10 ppm of steady value).



The devices are not restricted to standard resistance values, and can be supplied with “as required” values and ratios (e.g. 1.2345 kΩ vs.1 kΩ) at no extra cost or delivery time. The dividers are compliant to RoHS directive 2002/95/EC.Vishay Intertechnology, Inc. (NYSE: VSH) today announced that it is expanding its offering of Bulk Metal® Foil and Z-Foil ultra-high-precision voltage divider resistors with the release of eight new and enhanced devices, including the new high-power VFD244/Z and conformally coated VSH144/Z, and the enhanced 300144/5 and 300144Z/5Z.



All Foil devices released today offer a low typical TCR of ± 2 ppm/°C from - 55 °C to + 125 °C, + 25 °C ref., while the Z-Foil devices feature TCR of ± 0.05 ppm/°C typical from 0 °C to + 60 °C and ± 0.2 ppm/°C typical from - 55 °C to + 125 °C, + 25 °C ref. The Z-Foil resistors provide PCR tracking (“ΔR due to self heating”) of ±5 ppm at rated power.



The devices’ low TCR is combined with tight tolerances and excellent load-life stability values for precision instrumentation amplifiers, bridge networks, and differential amplifiers in high-end medical, military, aerospace, automatic test, and down-hole drilling equipment.



TCR



TCR tracking requires an absolute TCR of less than three times the tracking requirement. For example, TCR tracking of 2 ppm/°C requires the absolute TCR for the two resistors to be within 6 ppm/°C or better. TCR tracking is also a function of applied power (Joule effect, or PCR). The lower the absolute TCR, the lower the PCR.



High-Power VFD244 and VFD244Z Voltage Divider Resistors



The new VFD244 and VFD244Z offer a high power rating up to 1 W at + 70 °C, divided proportionally between the two elements, over a working voltage of 350 V. The VFD244 features TCR tracking of 0.5 ppm/°C, while the VFD244Z provides tracking down to 0.1 ppm/°C. Both devices offer tolerance matching to ± 0.005 % (50 ppm), a load-life stability ratio of < 0.005 % (50 ppm) at +70 °C for 2000 hours at rated power, and a resistance range from 1Ω to 150 kΩ.



Conformally Coated VSH144 and VSH144Z Voltage Divider Resistors



The conformally coated VSH144 and VSH144Z feature tolerance matching to ± 0.01 % (100 ppm), a load-life stability ratio of < 0.01 % (100 ppm) at +70 °C for 2000 hours at rated power, and a resistance range from 100 Ω to 20 kΩ. The VSH144 offers TCR tracking to 0.5 ppm/°C, while the VSH144Z provides tracking down to 0.1 ppm/°C. Both devices feature a power rating of 0.2 W at 70 °C, divided proportionally between the two elements, over a maximum working voltage of 200 V.



Enhanced 300144/5 and 300144Z/5Z Voltage Divider Resistors



The enhanced 300144/5 and 300144Z/5Z offer TCR tracking to 0.5 ppm/°C and 0.1 ppm/°C, respectively. Both Foil and Z-Foil devices provide tolerance matching to ± 0.005 % (50 ppm), a load-life stability ratio of < 0.005 % (50 ppm) at +70 °C for 2000 hours at rated power, and a resistance range from 100 Ω to 20 kΩ. The devices offer a power rating of 0.2 W at 70 °C, divided proportionally between the two elements, over a maximum working voltage of 200 V. The 300145/Z provides a pair of 300144/Z elements back to back in a single molded package.



Summary



All new and enhanced divider resistors released today offer a low voltage coefficient of < 0.1 PPM/V, current noise of < -40 dB, and thermal EMF of 0.05 µV/°C typical. The resistors provide an almost immeasurable 1-ns rise time (effectively without ringing), and a non-inductive (< 0.08 µH), non-capacitive design. The devices are available with standard tin/lead or lead-free terminations. Offering the utmost in ESD immunity, the resistors withstand electrostatic discharges up to 25 kV, for increased reliability.



The resistors offer low excess noise and high linearity, or low voltage coeffici