300144, 300145
Vishay Foil Resistors
Bulk Metal® Foil Technology High Precision Voltage Divider
Resistors with TCR Tracking to 0.5 ppm/°C and
Tolerance Match to 0.005 % (50 ppm)
FEATURES
Temperature coefficient of resistance (TCR)
absolute: ± 2 ppm/°C typical
(- 55 °C to + 125 °C, + 25 °C ref.)
TCR tracking: 0.5 ppm/°C
Tolerance: absolute and matching to 0.005 %
(50 ppm)
INTRODUCTION
Power rating: 0.2 W at 70 °C, for the entire resistive
element R1 and R2, divided proportionally between the two
values
Why tight tolerance is important?
Why do users employ tight tolerance resistors? A system or
a device or one particular circuit element must perform for a
specified period of time and at the end of that service period
it must still be performing within specifications.
During its useful life it may have been subjected to some
hostile service conditions and it is no longer within purchased
tolerance.
Load life ratio stability: < 0.005 % (50 ppm) 0.2 W at 70 °C
for 2000 h
Maximum working voltage: 200 V
Resistance range: 100R to 20K per resistive element
What is ratio?
Vishay Foil resistors are not restricted to standard
values/ratios; specific “as requested” values/ratios can be
supplied at no extra cost or delivery (e.g. 1K2345 vs. 1K)
The ratio tolerances available in a divider are variable and
dependent on resistor technology. Bulk Metal® foil provides
the tightest ratio tolerance available.
Electrostatic discharge (ESD) up to 25 000 V
Non-inductive, non-capacitive design
Rise time: 1 ns effectively no ringing
Thermal stabilization time < 1 s (nominal value achieved
within 10 ppm of steady state value)
The tight resolution capability and overall stability of foil
resistors permit adjustment within the divider to ratio not
available with other technologies. Ratios in network form, in
a common package have a better chance of holding tight
tolerances than those formed in a discrete matched set by
sorting.
Molded foil 300144, 300145 resistors can be provided in a
tolerance as tight as 0.005 %. Theoretically, ratios such as
these can be made initially with other resistor technologies.
However, less stable products will not hold these tight ratios
tolerances over time and applied stresses like voltage and
temperature.
Current noise: 0.010 µVRMS/V of applied voltage (< - 40 dB)
Thermal EMF: 0.05 µV/°C typical
Voltage coefficient: < 0.1 ppm/V
Non inductive: < 0.08 µH
Vishay Foil Resistors (VFR) Bulk Metal foil dividers/networks
300144, 300145 hold their ratio tolerances under defined
circumstances. Networks with tight ratio tolerances and
controlled tracking extend the useful life of equipment,
whether expressed as mean-time-between-failures (MTBF)
or service periods to recalibration or end-of-life-cycle.
Non hot spot design
Terminal finish: lead (Pb)-free or tin/lead alloy
Compliant to RoHS directive 2002/95/EC
Prototype quantities available in just 5 working days
or sooner. For more information, please contact
foil@vishaypg.com
How to avoid thermal EMF?
When the resistor’s terminals and the resistive element are
made of dissimilar metals and two junctions are at a different
temperature, a voltage is produced which is called “thermal
EMF”.
For better performances see 300144Z, 300145Z (Z-Foil)
datasheet
The level of voltage output is a function of the metals
involved and the differential temperature. The voltage
produced is either positive or negative depending on which
junction is considered as a reference point. Virtually all
resistive products have these metallic junctions. It is
presumed they will eventually be terminated to copper as a
final metallic combination and therefore copper is used as a
typical reference material.
APPLICATIONS
Instrumentation amplifiers
Bridge networks
Differential amplifiers
Military
Space
Medical
Automatic test equipment
R2
R1
V1
-
+
Vout
V2
R3
300144
300145
R4
300144, 300145 have the lowest thermal EMF’s because all
junctions have low microvolts outputs. Moreover,
construction of the resistive element is such that the input
and output junctions of the resistor are so close that the
temperature gradients between then is highly unlikely. These
design factors produce a divider with very low thermal EMF.
Our application engineering department is available to
advise and make recommendations. For non-standard
technical requirements and special applications. Please
contact us.
Down-hole (high temperature)
* Pb containing terminations are not RoHS compliant, exemptions may apply
Document Number: 63045
Revision: 16-Sep-13
For any questions, contact: foil@vishaypg.com
www.vishayfoilresistors.com
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