Y44870R10000F9R Datasheet, PDF (2/5 Pages) Vishay Siliconix – Bulk Metal® Technology High Precision, Current Sensing, Power Surface Mount, Metal Strip Resistor with Improved Stability 0.05 %, Resistance Value from 10 mΩ, Rated Power to 1 W and TCR to 0 ± 15 ppm/°C

CSM2512S
Vishay Foil Resistors
ABOUT CSM (Low Ohm Value 10 mΩ to 100 mΩ)
The CSM2512S series of low value current sense resistors
element, thereby minimizing temperature variations. Also,
provides power and precision in a four terminal, surface
the resistor element is designed to uniformly dissipate power
mount configuration. Its all welded construction is made up
of a Bulk Metal^® resistive element with plated copper
terminations. For low value resistors in precision applications
it is necessary to use four-terminal Kelvin connections to
T obtain a precise voltage drop across the resistive element.
In these applications, the contact resistance and the terminal
resistance may have the same order of magnitude or be
C _{even greater than that of the element resistance itself. Thus,}
significant error is introduced because the high temperature
coefficient of resistance of the leads and the contact
U resistance are unavoidably incorporated into the
measurements when the current sense resistor has only two
leads.
D _{Because the ability to measure low values to tolerances of}
0.1% or tighter is a concern to both the manufacturer and the
user, many situations require coordination of measurement
O ^{standards between both parties. Coordination is often}
accomplished by exchange of serialized units with recorded
readings to align measurement practices and specific
reference standards. The problem is compounded when
R _{high-precision current sensors under moderate to high}
power experience self-heating (Joule effect) which causes
P ^{the in-service resistance value to be different from that}
obtained using low current measurement equipment.
Therefore, the measurement conditions must be defined and
accepted at the time of spec preparation-that is, resistance
value as determined by specified current and measured
D _{IR-drop following a specified period of stabilization.}
Measurement equipment is available from a number of
E sources with varying stated accuracies. Traditional passive
current sensors and shunts generate heat under power,
which changes their resistance, and thus their voltage
V output. The CSM’s low absolute TCR reduces errors due to
temperature gradients, thus reducing a major source of
uncertainty in current measurement. The CSM can withstand
unconventional environmental conditions, including the
O _{extremely high temperatures and radiation-rich}
environments of down-hole oil exploration and well logging,
or the deep-sea underwater repeaters in cross-ocean
R _{communications. The stability of the CSM can be further}
enhanced by post-manufacturing operations (PMO), such as
temperature cycling, short-time overload, and accelerated
P _{load life which are uniquely applicable to Bulk Metal® Foil}
resistors. The device features a low thermal electromotive
force (EMF) that is critical in many precision applications.
IM ^{Thermal EMF in DC applications induces a voltage offset in}
the resistor that is equivalent to adding a small battery into
without creating hot spots, and the welded terminations
material is compatible with the element material. These
design factors result in a very low thermal-EMF(<3 µV/°C)
resistor, because in addition to the low thermal EMF
compatibility of the metals, the uniformity and thermal
efficiency of the design minimizes the temperature
differential across the resistor, thereby assuring low thermal
EMF generation at the leads. This further reduces the
“battery effect” exhibited by most current-sensing or
voltage-reference resistors. Thus, the parasitic voltage
generated at the junction of two dissimilar metals, which is
especially important in low-value current-sensing resistors, is
minimized, while the pure current-to-voltage conversion is
protected from such interference in DC applications.
The stability problems associated with analog circuits are
very pervasive, but knowledgeable selection of a few
high-quality resistors, networks, or trimming potentiometers
in critical locations can greatly improve circuit performance,
long-term application-related performance, as well as the
designer’s peace-of-mind. Additionally, the overall system
cost is often reduced when a knowledgeable designer
concentrates costs in a few exceptionally stable components
with minimal deviation and whose load and environmental
stability can often eliminate the necessity of additional
compensating circuitry or temperature-controlling systems.
The higher reliability and better overall system performances
also achieve excellent product results in the field, enhancing
market acceptance and product reputation. Designers often
unnecessarily pay for tighter tolerances than required simply
to accommodate the resistance stability shifts they know to
be imminent in an application due to the large
application-related changes in the components they
selected. Selection of a high-stability component like the
CSM in these applications eliminates the need for shift
allowance due to “planned instability” and allows the use of
looser initial tolerances than would otherwise be necessary.
the circuit.
The CSM’s all-welded construction is a Bulk Metal^® resistive
element with welded copper terminations, plated for
soldering. The terminations make a true continuous contact
with the resistive layer along the entire side of the resistive
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For any questions, contact: [e-mail]
Document Number: 63145
Revision: 3-May-11