Type SR Precision Current Sense Resistors
Type SR Current Sense Resistors utilize Caddock's Micronox® resistance
films to achieve a low cost resistor with Non-inductive Performance. This
compact construction makes this sense resistor ideal for many current
monitoring or control applications.
The special performance features of these Type SR Current Sense
Resistors include:
• Available in Standard Resistances down to 5 milliohm.
• Non-Inductive Design.
• Compact footprint.
Model No.
SR10
SR20
Min.
0.008 Ω
0.005 Ω
Non-inductive Design - Compact Footprint Minimizes Circuit Board Space
Kelvin Terminals (Four Wire) - Resistance Values 0.005Ω to 1.00Ω
• Terminals are constructed for Kelvin connections to the circuit board.
Resistance
Max.
1.00 Ω
1.00 Ω
Power Rating at
70°C
1.0 Watt
2.0 Watts
*
Voltage Rating
Power Limited
Power Limited
Terminal Material
Solderable
Solderable
SR10 Standard Resistance Values:
0.008
0.010
0.012
0.015
Ω
Ω
Ω
Ω
0.020
0.025
0.030
0.033
Ω
Ω
Ω
Ω
0.040
Ω
0.050
Ω
0.075
Ω
0.10
Ω
0.15
0.20
0.25
0.30
Ω
Ω
Ω
Ω
0.40
0.50
0.75
1.00
SR10 PACKAGE DIMENSIONS
Front view
.365 ±.020
(9.27 ±.51)
.370 ±.015
(9.40 ±.38)
.125 ±.020
(3.18 ±.51)
.045 (1.14)
.025 (.64)
Side view
.090 (2.29)
MAX.
Back view
Ω
Ω
Ω
Ω
SR10
0.025Ω
1%
.032 ±.007
(.81 ±.18)
SR20 PACKAGE DIMENSIONS
.565 ±.020
(14.35 ±.51)
.090 MAX.
(2.29 MAX.)
.400 ±.015
(10.16 ±.38)
.125 ±.020
(3.18 ±.51)
.032 ±.007
(.81 ±.18)
SR20
0.050Ω
1%
0.040
Ω
0.15
Ω
0.40
Ω
0.005
Ω
0.020
Ω
0.050
Ω
0.20
Ω
0.50
Ω
0.008
Ω
0.025
Ω
0.075
Ω
0.25
Ω
0.75
Ω
0.010
Ω
0.030
Ω
0.10
Ω
0.015
Ω
0.033
Ω
0.30
Ω
1.00
Ω
Custom resistance values can be manufactured for
high quantity applications. Please contact Caddock
Applications Engineering.
Resistance Tolerance:
±1.0%
Temperature Coefficient:
TC referenced to
+25°C,
∆R
taken at -15°C and +105°C.
0.081 to 1.00 ohm
-50 to +100 ppm/°C
0.025 to 0.080 ohm
0 to +150 ppm/°C
0.008 to 0.024 ohm
0 to +200 ppm/°C
0.005 to 0.007 ohm
0 to +300 ppm/°C
Load Life:
1000 hours at rated power at +70°C,
∆R
±(0.2 percent + 0.00001 ohm) max.
Thermal Shock:
Mil-Std-202, Method 107, Cond. A,
∆R
±(0.2 percent + 0.00001 ohm) max.
Moisture Resistance:
Mil-Std-202, Method 106,
∆R
±(0.2 percent + 0.00001 ohm) max.
Encapsulation:
Polymer over resistance element.
Power Derating Curve:
100
80
*
Power rating:
The power rating
60
40
should be limited as
20
shown by the derating
0
curve based upon the
25
70
100
150
TEMPERATURE, °C
maximum ambient
temperature. The derating curve is based on still
air with natural convection around the resistor.
SR20 Standard Resistance Values:
Specifications:
.045 (1.14)
.025 (.64)
DIMENSIONS IN INCHES AND (MILLIMETERS)
CIRCUIT BOARD LAYOUT NOTES
SR10
SR20
A
Scale:
actual size
A
.100 (2.54)
.100 (2.54)
.100 (2.54)
B
B
.200 (5.08)
.100 (2.54)
.200 (5.08)
.045 (1.14)
.025 (.64)
.045 (1.14)
.045 (1.14)
.025 (.64)
.045 (1.14)
Measurement note: For purposes of these specifications, resistance measurement shall
be made using Kelvin connections (four wire) with appropriate current and sense con-
nections to the device terminals.
C = Current connection
S = Sense connection
Circuit Board Layout: The circuit board traces connecting to the current terminals must
be sized appropriately for the current flowing through the trace. For example; 0.005Ω
operated at 2.0 Watts would have 20 amps flowing through the circuit board traces into
the current terminals.
Applications Engineering
17271 North Umpqua Hwy.
Roseburg, Oregon 97470-9422
Phone: (541) 496-0700
Fax: (541) 496-0408
© 2003-2007 Caddock Electronics, Inc.
Section AA
.025 (.64)
Section BB
.025 (.64)
Ordering Information:
Model Number:
Resistor Value:
SR10 - 0.050 - 1%
RATED LOAD, %
C S S C
C
S S
C
Tolerance
e-mail: caddock@caddock.com • web: www.caddock.com
For Caddock Distributors listed by country see caddock.com/contact/dist.html
ELECTRONICS, INC.
Sales and Corporate Office
1717 Chicago Avenue
Riverside, California 92507-2364
Phone: (951) 788-1700
Fax: (951) 369-1151
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