Type SR Precision Current Sense Resistors
Non-inductive Design - Compact Footprint Minimizes Circuit Board Space
Kelvin Terminals (Four Wire) - Resistance Values 0.005Ω to 1.00Ω
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.
• Terminals are constructed for Kelvin connections to the circuit board.
• Compact footprint.
Resistance
Power Rating at
Voltage Rating
Terminal Material
Model No.
70°C
Min.
Max.
*
SR10
SR20
0.008 Ω
1.00 Ω
1.0 Watt
Power Limited
Power Limited
Solderable
Solderable
2.0 Watts
0.005 Ω
1.00 Ω
SR10 Standard Resistance Values:
0.008 Ω 0.020 Ω
0.010 Ω 0.025 Ω
0.012 Ω 0.030 Ω
0.015 Ω 0.033 Ω
0.040 Ω 0.15 Ω 0.40 Ω
0.050 Ω 0.20 Ω 0.50 Ω
0.075 Ω 0.25 Ω 0.75 Ω
SR10 PACKAGE DIMENSIONS
Side view
Back view
Front view
0.10 Ω
0.30 Ω 1.00 Ω
.090 (2.29)
.365 ±.020
(9.27 ±.51)
MAX.
SR20 Standard Resistance Values:
SR10
0.025Ω
1%
.370 ±.015
(9.40 ±.38)
0.005 Ω 0.020 Ω
0.008 Ω 0.025 Ω
0.010 Ω 0.030 Ω
0.015 Ω 0.033 Ω
0.040 Ω 0.15 Ω 0.40 Ω
0.050 Ω 0.20 Ω 0.50 Ω
0.075 Ω 0.25 Ω 0.75 Ω
.125 ±.020
(3.18 ±.51)
0.10 Ω
0.30 Ω 1.00 Ω
.045 (1.14)
.025 (.64)
.032 ±.007
(.81 ±.18)
Custom resistance values can be manufactured for
high quantity applications. Please contact Caddock
Applications Engineering.
SR20 PACKAGE DIMENSIONS
.565 ±.020
(14.35 ±.51)
.090 MAX.
Specifications:
(2.29 MAX.)
Resistance Tolerance: ±1.0%
SR20
0.050Ω
1%
.400 ±.015
(10.16 ±.38)
Temperature Coefficient: TC referenced to
+25°C, ∆R taken at -15°C and +105°C.
.125 ±.020
(3.18 ±.51)
.045 (1.14)
.025 (.64)
0.081 to 1.00 ohm
0.025 to 0.080 ohm
0.008 to 0.024 ohm
0.005 to 0.007 ohm
-50 to +100 ppm/°C
0 to +150 ppm/°C
0 to +200 ppm/°C
0 to +300 ppm/°C
.032 ±.007
(.81 ±.18)
DIMENSIONS IN INCHES AND (MILLIMETERS)
CIRCUIT BOARD LAYOUT NOTES
Load Life: 1000 hours at rated power at +70°C,
∆R ±(0.2 percent + 0.00001 ohm) max.
SR20
SR10
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.
B
B
A
A
Scale:
actual size
.200 (5.08)
.100 (2.54)
.200 (5.08)
Encapsulation: Polymer over resistance element.
.100 (2.54)
.100 (2.54)
.100 (2.54)
Power Derating Curve:
100
C
S
S
C
S S C
C
Power rating:
The power rating
80
*
60
.045 (1.14)
.025 (.64)
.045 (1.14)
.025 (.64)
.045 (1.14)
.025 (.64)
.045 (1.14)
.025 (.64)
40
should be limited as
20
shown by the derating
Section BB
Section AA
0
curve based upon the
25
70
100
150
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.
TEMPERATURE, °C
maximum ambient
temperature. The derating curve is based on still
air with natural convection around the resistor.
C = Current connection
S = Sense connection
Ordering Information:
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.
SR10 - 0.050 - 1%
Tolerance
Model Number:
Resistor Value:
Applications Engineering
17271 North Umpqua Hwy.
Roseburg, Oregon 97470-9422
Phone: (541) 496-0700
Fax: (541) 496-0408
Sales and Corporate Office
1717 Chicago Avenue
Riverside, California 92507-2364
Phone: (951) 788-1700
ELECTRONICS, INC.
For Caddock Distributors listed by country see caddock.com/contact/dist.html
e-mail: caddock@caddock.com • web: www.caddock.com
Fax: (951) 369-1151
© 2003-2007 Caddock Electronics, Inc.
28_IL126.0507