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Vishay Bolsters Offering of Bulk Metal® Foil and Z-Foil Ultra-High-Precision Voltage Divider Resistors With Release of New High-Power VFD244/Z, Conformally Coated VSH144/Z, and Enhanced 300144/5 and 300144Z/5Z
Devices Feature TCR Down to ± 0.05 ppm/°C typical, TCR Tracking to 0.1 ppm/°C, and Tolerance Matching to ± 0.005 % (50 ppm) for High-Precision Applications
MALVERN, Pa. — April 16, 2010 — 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 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.
Precision Voltage Divider Resistors − Device Specification Table:
Part# VFD244 VFD244Z VSH144 VSH144Z 300144/5 300144Z/5Z
Feature Wide Value Range and High Power Small Profile and Conformal
Coated
300144/Z -
Molded Voltage Divider
300145/Z -
Two Independent Voltage Dividers in One Package
TCR
(Typical)
± 2** ppm/°C ± 0.05* ppm/°C
± 0.2** ppm/°C
± 2** ppm/°C ± 0.05* ppm/°C
± 0.2** ppm/°C
± 2** ppm/°C ± 0.05* ppm/°C
± 0.2** ppm/°C
TCR Tracking
(Typical)
0.5 ppm/°C 0.1 ppm/°C 0.5 ppm/°C 0.1 ppm/°C 0.5 ppm/°C 0.1 ppm/°C
Tolerance
Matching
0.005 % 0.005 % 0.01 % 0.01 % 0.005 % 0.005 %
Load Life
Stability Ratio
< 0.005 % < 0.005 % < 0.01 % < 0.01 % < 0.005 % < 0.005 %
Power Rating
(@ 70°C)
1 W to
1 Ω < 100 kΩ
1 W 0.2 W 0.2 W 0.2 W 0.2 W
0.6 W to
100 kΩ to 150 kΩ
Max Working Voltage 350 V 350 V 200 V 200 V 200 V 200 V
Resistance
Range
1 Ω to 150 kΩ 1 Ω to 100 kΩ 100 Ω to 20 kΩ 100 Ω to 20 kΩ 100 Ω to 20 kΩ 100 Ω to 20 kΩ
*Temperature Range: 0 °C to + 60 °C
**Temperature Range: - 55 °C to + 125 °C, + 25 °C ref.
Samples and production quantities of the new divider resistors are available now, with lead times of five days for samples, and six weeks for standard orders.
Vishay Precision Group Inc. has ceased to be a subsidiary of Vishay Intertechnology Inc. and is an independent publicly owned company.