CSM3637P
Ultra High Precision, Surface Mount 4-Terminal Precision Resistor with
Increased Power to 5W (40A max), Resistance Values from
3 mto 100 m, and TCR to ± 15 ppm/°C
FEATURES
Resistance range: 3 m to 100 m
Temperature coefficient of resistance (TCR):
3 mto 100m : 15 ppm/°C maximum
Load life stability: ± 0.2 % (70 °C, 2000 h at rated
power)
INTRODUCTION
The CSM3637P is a low value current sense resistor,
providing 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.
There are many current sense resistors on the market. Until
now the combination of very stable and precise resistors
with low TCR of ± 15 ppm/°C maximum, tight tolerance of
± 0.1 % and load life stability of ± 0.2 % (2000 h, + 70 °C at
rated power) was not easily available.
The key performance of the new CSM3637P is its high rated
power up to 5W. This option became available due to a
special design which consists of a heat sink on the top of the
resistive element, thus allowing a better heat dissipation.
These specifications are based on tests performed in
accordance with methods prescribed by appropriate
MIL-PRF standards (MIL-PRF-55342 and MIL-PRF-49465).
The four terminal device separates the current leads from
the voltage sensing leads. This configuration eliminates the
effect of the lead wire resistance from points A to B and
C to D.
In addition, a key feature of the CSM3637P is its low thermal
EMF design (very important for low ohmic value DC
applications). The welded terminals make intimate contact
with the chip thereby minimizing temperature differentials.
Our application engineering department is available to
advise and make recommendations.
For non-standard technical requirements and special
applications, please contact:
foil@vpgsensors.com
Power rating: to 5 W (see Table 1)
Resistance tolerance: to ± 0.1 %
Vishay Foil Resistors (VFR) are not restricted to standard
values; specific “as required” values can be supplied at no
extra cost or delivery (e.g. 10.2345 m vs. 10 m)
Short time overload: ± 0.2 % typical
Proprietary processing technique produces extremely low
resistance values with improved stability
All welded construction
Solderable terminations
Very low inductance 0.5 nH
Excellent frequency response to 50 MHz
Low thermal EMF < 3 µV/°C (DC offset error, significant for
low values)
Maximum current: up to 40 A
Four terminal (Kelvin) design: allows for precise and
accurate measurements
Terminal finishes available: lead (Pb)-free, tin/lead alloy
Prototype quantities available in just 5 working days
or sooner. For more information, please contact
foil@vpgsensors.com
For better performances, please contact us
FIGURE 1 - POWER DERATING CURVE
+ 70 °C
100
Rated Power (%)
B
I
A
Z
in
R
C
I
D
80
60
40
20
0
- 65 - 50
- 25
0
25
50
75
100
125
150
170
Ambient Temperature (°C)
~
∞
=
For any questions, contact
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1
V
* This datasheet provides information about parts that are RoHS-compliant and/or parts that are non-RoHS-compliant. For example, parts with
lead (Pb) terminations are not RoHS-compliant. Please see the information/tables in this datasheet for details.
Document Number: 63210
Revision: 13-Oct-15
CSM3637P
ABOUT CSM3637P
This new high-precision Bulk Metal
®
surface-mount Power
Metal Strip
®
resistor features an improved load-life stability
of ± 0.2 % at + 70 °C for 2000 h at rated power, an absolute
TCR of ± 15 ppm/°C maximum from - 55 °C to + 125 °C,
+ 25 °C ref., and a tolerance of ± 0.1 %.
Typical current sensing resistors exhibit 2000 hour load-life
changes more than 5 times greater than the CSM3637P. The
improved resistance stability of the CSM Series makes it
ideal for tightened-stability voltage division and precision
current sensing applications in switching linear power
supplies, power amplifiers, measurement instrumentation,
bridge networks, and medical and test equipment.
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 of
± 15 ppm/°C reduces errors due to temperature changes,
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 CSM3637P 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 Technology.
The device features a low thermal electromotive force (EMF)
that is critical in many precision DC applications. The CSM’s
all-welded construction is composed of a Bulk Metal
®
resistive element with welded copper terminations, plated for
soldering. The terminations make true ohmic 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 DC 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 whose proven minimal-
deviation 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 be necessary with
current-sensing resistors based on other technologies.
The Key Applications
Applications requiring accuracy and repeatability under
stress conditions such as the following:
Switching and linear power supplies
Precision current-sensing
Power management systems
Feedback circuits
Power amplifiers
Measurement instrumentation
Precision instrumentation amplifiers
Medical and automatic test equipment
Satellites and aerospace systems
Commercial and Military avionics
Test and measurement equipment
Electronic scales
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Document Number: 63210
Revision: 13-Oct-15
CSM3637P
TABLE 1 - SPECIFICATIONS
PARAMETER
Resistance Range
Power Rating at 70 °C in free air
Maximum Current
Tightest Tolerance
Temperature Coefficient Of Resistance (TCR)
(- 55 °C to + 125 °C, + 25 °C ref.)
Thermal EMF
Operating Temperature Range
Weight (maximum)
CSM3637P
3 m to 100 m
5W
(
3m to 10m)
4W (>10m to 100m)
40 A
± 0.1 %
3 m
to 100m
:15 ppm/°C maximum
< 3 µV/°C
- 65 °C to + 170 °C
0.38 g
FIGURE 2 - DIMENSIONS AND IMPRINTING
in inches (millimeters)
CSM3637P DIMENSIONS
CSM3637P LAND PATTERN
E
1
I
1
H
1
A
B
I
L
T
W
a
E
2
c
H
2
I
2
d
b
DIMENSIONS - TOLERANCES ± 0.010 (± 0.254)
RESISTANCE RANGE (m)
3 to 100
L
0.360 (9.144)
W
0.370 (9.398)
H
1
0.025 (0.635)
H
2
0.060 (1.524)
max
T
0.086 (2.184)
A
0.061 (1.549)
B
0.032 (0.813)
LAND PATTERN DIMENSIONS - TOLERANCES ± 0.003 (± 0.076)
RESISTANCE RANGE (m)
3 to 100
l
0.178 (4.52)
b
0.390 (9.91)
-
-
a
0.116 (2.95)
c
0.066 (1.68)
d
0.024 (0.610)
CSM3637P CONSTRUCTION
1. Resistive element
2. Copper terminal with solderable finish
3. Terminal-to-element weld
4. Thermal conductive adhesive
5. Anodized aluminum heat sink
5
4
1
3
2
Document Number: 63210
Revision: 13-Oct-15
For any questions, contact
foil@vpgsensors.com
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3
CSM3637P
TABLE 2 - CSM3637P ENVIRONMENTAL PERFORMANCE COMPARISON
3 m
to 100 m
TEST
Thermal Cycling
Load Life Stability
Bias Humidity
Short Time Overload
High Temperature Exposure
Low Temperature Storage
Moisture Resistance
Shock
Vibration
Resistance to Soldering Heat
Solderability
(1)
CONDITIONS
- 55 °C to + 125 °C, 1000 cycles,
15 min at each extreme
2000 h, 70 °C at rated power
85 °C, 85 % humidity, 10 % bias, 1000 h
2.5 x rated power for 5 s
1000 h, 170 °C
MIL-PRF-49465
MIL-STD-202, method 106, 0 % power,
7a and 7b not required
100 g, 6 ms
(10 Hz to 2000 Hz) 20 g
10 s to 12 s at + 260 °C
MIL-STD-202
MIL-PRF-49465B
R
LIMITS
± (0.5 % + 0.0005R)
± (1.0 % + 0.0005R)
± (0.5 % + 0.0005R)
± (0.5 % + 0.0005R)
± (1.0 % + 0.0005R)
± (0.5 % + 0.0005R)
± (0.5 % + 0.0005R)
± (0.1 % + 0.0005R)
± (0.1 % + 0.0005R)
± (0.25 % + 0.0005R)
95 % coverage
TYPICAL
R
LIMITS
0.1 %
0.2 %
0.05 %
0.2 %
0.2 %
0.05 %
0.02 %
0.02 %
0.02 %
0.05 %
-
MAXIMUM
R
LIMITS
(1)
0.3 %
0.6 %
0.2 %
0.5 %
0.3 %
0.1 %
0.05 %
0.05 %
0.05 %
0.1 %
Add 0.0005R as per MIL-PRF-49465B
FIGURE 3 - CSM3637P UNDER LOAD TEMPERATURE RISE OVER AMBIENT, TYPICAL
250
Resistor Element
200
ΔT, °C
150
100
50
0
Top Heatsink
0
1
2
3
4
5
6
Power, W
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Document Number: 63210
Revision: 13-Oct-15
CSM3637P
TABLE 3 - GLOBAL PART NUMBER INFORMATION
(1)
NEW GLOBAL PART NUMBER: Y14740R05000E0W (preferred part number format)
DENOTES PRECISION
Y
VALUE
R
=
CHARACTERISTICS
0
= standard part, tin/lead termination
9
= standard part, lead (Pb)-free termination
1 to 999
= custom
Y
1
4
7
4
0
R
0
5
0
0
0
E
0
W
PRODUCT CODE
1474
= CSM3637P
RESISTANCE TOLERANCE
B
C
D
E
F
= ± 0.1%
= ± 0.25 %
= ± 0.5 %
= ± 0.2 %
= ± 1.0 %
PACKAGING
W
= waffle pack
FOR EXAMPLE: ABOVE GLOBAL ORDER Y1474 0R05000 E 0 W:
TYPE: CSM3637P
VALUE: 50 m
ABSOLUTE TOLERANCE: ± 0.2 %
TERMINATION: standard tin/lead
PACKAGING: waffle pack
HISTORICAL PART NUMBER: CSM3637P 0R05 E B T (will continue to be used)
CSM3637P
MODEL
0R05
OHMIC VALUE
0R05
= 0.05
B
C
D
E
F
E
ABS. TOLERANCE
= ± 0.1%
= ± 0.25 %
= ± 0.5 %
= ± 0.2 %
= ± 1.0 %
B
TERMINATION
S
= lead (Pb)-free
B
= tin/lead
W
PACKAGING
W
= waffle pack
Note
(1)
For non-standard requests, please contact application engineering.
Document Number: 63210
Revision: 13-Oct-15
For any questions, contact
foil@vpgsensors.com
www.vishayfoilresistors.com
5
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