General Note
IRC reserves the right to make changes in product specification without notice or liability.
All information is subject to IRC’s own data and is considered accurate at time of going to print. A subsidiary of
TT electronics plc
• 4222 South Staples Street • Corpus Christi Texas 78411 USA
Wire and Film Technologies Division
Telephone: 361 992 7900 • Facsimile: 361 992 3377 • Website: www.irctt.com
SPH/SPF Series
• SPF is fusible
• ±5%, ±10% tolerance
• 0.1 ohm to 2400 ohms
• Weldable and solderable leads
• 2 watt rated with 1 watt dimensions
• Drop-in replacement for BWH/BWF
• Lead free, RoHS compliant construction available
• TCR’s as low as ±150 ppm/°C standard (custom TC’s available)
General Purpose Failsafe
Molded Wirewound Resistor
Electrical Data
IRC Type SPH SPF
EIA RS-344 Style CRU2 CRU2
MIL-R-11 Style RC32/RC42 RC32/RC42
Resistance - Std. 0.1Ω to 2400Ω0.1Ω to 1000Ω
Tolerance - Std. ±5%, ±10% ±5%, ±10%
Power Rating
2 watt @ 70°C
1 watt @ 115°C
Derating to 0 @ 160°C
2 watt @ 70°C
1 watt @ 115°C
Derating to 0 @ 160°C
Max. Continuous Working Voltage √PR √PR
Min. Insulation
Resistance
10,000 Meg
100 Meg
10,000 Meg
100 Meg
Min. Dielectric ATM
Withstanding Volts
(RMS) Reduced Pressure
1000V
625V
1000V
625V
Hotspot Temperature Rise 145°C @ 2 watts 145°C @ 2 watts
Typical Load Life 5% 5%
Current Noise Negligible Negligible
Dry
Wet
1. Resistive Element
All resistor types have resistance alloy
winding on a braided fiberglass substrate.
Intermediate silicone coatings are used
to enhance processibility and to provide
protection to the resistive element.
2. Termination
The SPH and SPF resistors are terminated
using an alloy coated copper flashed steel
lead welded to a cap of the same material.
This termination assembly is mechanically
crimped, utilizing an improved crimp design,
to the resistive element.
3. Encapsulation
The SPH and the SPF are encapsulated uti-
lizing a compression molded phenolic plastic
material. The SPF has a flame resistance
coating applied over the resistive element
to provide flammability protection when
destructive overloads may occur.
4. Marking
All products are marked utilizing heat and
solvent resistant color code bands consistent
with EIA/MIL requirements. The first band
is double width to designate wirewound
construction. A fifth band, blue in color, is
used for flameproof identification.
1
3
4
2
(See notes below)
SPH/SPF Series Issue December 2008 Sheet 1 of 3
• 4222 South Staples Street • Corpus Christi Texas 78411 USA
Wire and Film Technologies Division
Telephone: 361 992 7900 • Facsimile: 361 992 3377 • Website: www.irctt.com
Dimensions (Inches and (mm))
IRC Type A B C D
SPH 0.562 ± 0.010
(14.3 ± 0.25)
0.225 ± 0.008
(5.72 ± 0.20)
0.032 ± 0.002
(0.813 ± 0.05)
1.50 ± 0.126
(38.1 ± 3.2)
SPF 0.562 ± 0.010
(14.3 ± 0.25)
0.225 ± 0.008
(5.72 ± 0.20)
0.032 ± 0.002
(0.813 ± 0.05)
1.50 ± 0.126
(38.1 ± 3.2)
Physical Data
C
DA
B
General Purpose Failsafe
Molded Wirewound Resistor
Environmental Data
Test SPH SPF
Temperature Coefficient (ppm)*
0.1Ω - 0.16Ω ± 1000
0.18Ω - 0.68Ω ± 800
0.75Ω - 2400Ω ± 400
0.10Ω ± 1700
0.11Ω - 0.16Ω ± 1000
0.18Ω - 0.68Ω ± 800
0.75Ω - 1000Ω ± 400
Dielectric Withstanding Voltage (RMS) 1000V 1000V
Momentary Overload 5% 5%
Low Temperature Operation 5% 5%
Temperature Cycle 5% 5%
Humidity 5% 5%
Load Life 5% 5%
Terminal Strength 5% 5%
Resistance to Solder Heat 5% 5%
Solderability No Failures No Failures
SPH/SPF Series Issue December 2008 Sheet 2 of 3
• 4222 South Staples Street • Corpus Christi Texas 78411 USA
Wire and Film Technologies Division
Telephone: 361 992 7900 • Facsimile: 361 992 3377 • Website: www.irctt.com
Sample Part No.
IRC Type
Resistance Range
Tolerance
J = 5%, K = 10%
Lead Free Construction
Ordering Data
SPH 1500 J LF
SPH Power Derating Curve
2.0
2.5
1.5
1.0
0.5
0
Ambient Temperature (°C)
Power (watts)
0 50 100 150 20070 160
General Purpose Failsafe
Molded Wirewound Resistor
SPF Power Derating Curve
SPF Typical Fusing SPH and SPF
Temperature Rise Chart
2.0
2.5
1.5
1.0
0.5
0
Ambient Temperature (°C)
Power (watts)
0 50 100 150 20070
20
25
15
10
5
0
Time (seconds)
Power (watts)
0 20 40 60 80 100
2
0.1 ohm
1 ohm
10 ohm
100 ohm
1000 ohm
125
150
100
75
50
25
Power Input (watts)
Temperature Rise (°C)
0 0.5 1.0 1.5 2.0
0
SPH/SPF Series Issue December 2008 Sheet 3 of 3
