Bulk Metal
®
Technology High Precision, Current Sensing, Power Surface
Mount, Metal Strip Resistor with Improved Stability 0.05 %, Resistance
Value from 10 m
, Rated Power to 1 W and TCR to 0 ± 15 ppm/°C
Document Number: 63145 For any questions, contact www.vishayfoilresistors.com
Revision: 4-Mar-15 foil@vpgsensors.com 1
CSM2512S
The CSM’s series of low value current sense resistors
provides power and precision in a four terminal, surface
mount configuration. Its all welded construction is made
up of a Bulk Metal® resistive element with plated copper
terminations.
Vishay Foil Resistors’ application engineering department is
available to advise and make recommendations.
For non-standard technical requirements and special
applications, please contact foil@vpgsensors.com.
I
A
R
Zin
I
D
V
=
~∞
BC
FEATURES
Temperature coefficient of resistance (TCR):
(- 55 °C to + 125 °C, + 25 °C ref.)
± 15 ppm/°C maximum
± 10 ppm/°C maximum on special request
Load life stability to ± 0.05 % (70 °C, 2000 h
at rated power)
Power rating: 1 W
Resistance tolerance: ± 0.1 %
Resistance range: 10 m to 100 m
Vishay Foil resistors are not restricted to standard values,
we can supply specific “as required” values at no extra cost
or delivery (e.g. 10.2345 m vs. 10 m)
Short time overload: ± 0.1 % typical
Thermal EMF: < 3 µV/°C
Maximum current: up to 10 A
Surface mount configuration
Four terminal (Kelvin) design: allows for precision accurate
measurements
Terminal finishes available: lead (Pb)-free, tin/lead alloy
Screening in accordance with EEE-INST002 available
(Per MIL-PRF-55342 and MIL-PRF-49465; see
datasheets of 303144 and 303145 )
Prototype quantities available in just 5 working days or
sooner. For more information, please contact
foil@vpgsensors.com
For better performances please contact Application
Engineering
FIGURE 1 - POWER DERATING CURVE
- 65 - 50 - 25 0 25 50 75 100 125 150 170
Ambient Temperature (°C)
100
80
60
40
20
0
Rated Power (%)
+ 70 °C
TABLE 1 - PERFORMANCE SPECIFICATIONS
PARAMETER CSM2512S
Resistance Range 10 m to 100 m
Power Rating at 70 °C 1 W
Maximum Current 10 A
Maximum Working Voltage (P x R)1/2
Tightest Tolerance ± 0.1 %
Temperature Coefficient Maximum (- 55 °C to + 125 °C, + 25 °C ref.) ± 15 ppm/°C, ± 10 ppm/°C is available
Operating Temperature Range - 65 °C to + 170 °C
Weight (maximum) 0.09 g
* Pb containing terminations are RoHS compliant, exemptions may apply
www.vishayfoilresistors.com For any questions, contact Document Number: 63145
2 foil@vpgsensors.com Revision: 4-Mar-15
CSM2512S
ABOUT CSM (Low Ohm Value 10 m to 100 m)
The CSM2512S series of low value current sense resistors
provides power and precision in a four terminal, surface
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
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
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
resistance are unavoidably incorporated into the
measurements when the current sense resistor has only two
leads.
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
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
high-precision current sensors under moderate to high
power experience self-heating (Joule effect) which causes
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
IR-drop following a specified period of stabilization.
Measurement equipment is available from a number of
sources with varying stated accuracies. Traditional passive
current sensors and shunts generate heat under power,
which changes their resistance, and thus their voltage
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
extremely high temperatures and radiation-rich
environments of down-hole oil exploration and well logging,
or the deep-sea underwater repeaters in cross-ocean
communications. The stability of the CSM can be further
enhanced by post-manufacturing operations (PMO), such as
temperature cycling, short-time overload, and accelerated
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.
Thermal EMF in DC applications induces a voltage offset in
the resistor that is equivalent to adding a small battery into
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
element, thereby minimizing temperature variations. Also,
the resistor element is designed to uniformly dissipate power
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.
FIGURE 2 - DIMENSIONS AND IMPRINTING in inches (millimeters)
CSM2512S DIMENSIONS
H
A
W
B
T
L
(1)
CSM2512S LAND PATTERN
Kelvin Connection
I
1
, I
2
- Current
E
1
, E
2
- Sense
e
I
a
dc
b
E1
E2
I1
I2
DIMENSIONS - TOLERANCES ± 0.010 (± 0.254), * ± 0.015 (± 0.381)
RESISTANCE RANGE () L W H T A B
0.01 to 0.1 0.250 (6.350) 0.125 (3.175) 0.025 (0.635) 0.030 (0.762) 0.030 (0.762)* 0.032 (0.813)*
LAND PATTERN DIMENSIONS - TOLERANCES ± 0.003 (± 0.076)
RESISTANCE RANGE () l b e a c d
0.01 to 0.1 0.160 (4.06) 0.145 (3.68) 0.055 (1.39) 0.065 (1.65) 0.045 (1.14) 0.021 (0.53)
Document Number: 63145 For any questions, contact www.vishayfoilresistors.com
Revision: 4-Mar-15 foil@vpgsensors.com 3
CSM2512S
Note
(1) White dots indicate top side of part for mounting purposes
TABLE 2 - CSM2512S PERFORMANCE SPECIFICATIONS
TEST CONDITIONS MIL-PRF-49465B
R LIMITS
TYPICAL R
LIMITS
MAXIMUM
R LIMITS
Thermal Shock - 55 °C to + 150 °C, 1000 cycles, 15 min at
each extreme ± (0.5 % + 0.0005R) 0.1 % 0.2 %
Load Life Stability 2000 h, 70 °C at rated power ± (1.0 % + 0.0005R) 0.05 % 0.2 %
Bias Humidity 85 °C, 85 % humidity
10 % bias, 1000 h ± (0.5 % + 0.0005R) 0.05 % 0.2 %
Short Time Overload 5 x rated power for 5 s ± (0.5 % + 0.0005R) 0.1 % 0.2 %
High Temperature Exposure 1000 h, 170 °C ± (1.0 % + 0.0005R) 0.2 % 0.3 %
Low Temperature Storage MIL-PRF-49465 ± (0.5 % + 0.0005R) 0.05 % 0.1 %
Moisture resistance MIL-STD-202, method 106, 0 % power,
7a and 7b not required ± (0.5 % + 0.0005R) 0.02 % 0.05 %
Shock 100 g, 6 ms ± (0.1 % + 0.0005R) 0.02 % 0.05 %
Vibration (10 Hz to 2000 Hz) 20 g ± (0.1 % + 0.0005R) 0.02 % 0.05 %
Resistance to Soldering Heat 10 s to 12 s at + 260 °C ± (0.25 % + 0.0005R) 0.05 % 0.1 %
Solderability MIL-STD-202 95 % coverage -
FIGURE 3 - LOAD LIFE RESULTS OF CSM2512S VS. CSM2512
-1500
-1000
-500
0
500
1000
1500
0 500 1000 1500 2000 2500
R/R (ppm)
Time (Hours)
CSM2512S 0R05
Load Life 2000 HRS @ 1 W @ +70°C (15 units)
-3000
-2500
-2000
-1500
-1000
-500
0
500
1000
1500
2000
2500
3000
0 500 1000 1500 2000
R/R (ppm)
Time (Hours)
CSM2512 0R05
Load Life 2000 HRS @ 1 W @ +70°C (15 units)
TABLE 3 - GLOBAL PART NUMBER INFORMATION
NEW GLOBAL PART NUMBER: Y44870R10000B0R (preferred part number format)
DENOTES PRECISION VALUE CHARACTERISTICS (1)
Y R = 0 = standard part, tin/lead termination
9 = standard part, lead (Pb)-free termination
1 - 999 = custom
PRODUCT CODE RESISTANCE TOLERANCE PACKAGING
4487 = CSM2512S B= ± 0.1 %
C= ± 0.25 %
D= ± 0.5 %
F= ± 1.0 %
W= waffle pack
R= tape and reel
FOR EXAMPLE: ABOVE GLOBAL ORDER Y4487 0R10000 B 0 R:
TYPE: CSM2512S
VALUE: 100.0 m
ABSOLUTE TOLERANCE: ± 0.1 %
TERMINATION: standard tin/lead
PACKAGING: tape and reel
HISTORICAL PART NUMBER: CSM2512S 0R1000 B B T (will continue to be used)
CSM2512S 0R1000 B B T
MODEL OHMIC VALUE ABS. TOLERANCE TERMINATION PACKAGING
0R1000 = 0.100 B= ± 0.1 %
C= ± 0.25 %
D= ± 0.5 %
F= ± 1.0 %
S= lead (Pb)-free
B= tin/lead
T= tape and reel
W= waffle pack
www.vishayfoilresistors.com For any questions, contact Document Number: 63145
4 foil@vpgsensors.com Revision: 4-Mar-15
CSM2512S
Note
(1) For non-standard requests, please contact application engineering.
4870 100RY4 B00 R0
Vishay Precision Group, Inc.
www.vpgsensors.com
1
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Document No.: 63999
Revision: 15-Jul-2014
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