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
Advanced Film Division • 4222 South Staples Street • Corpus Christi Texas 78411 USA
Telephone: 361 992 7900 • Facsimile: 361 992 3377 • Website: www.irctt.com LRF3W-MIL Series Issue April 2010
Low Range 3 Watt
Mil Chip Resistor
• Tolerances to ±1%
• 3 Watt @70°C power dissipation in a compact 1225 package
• Resistance range from 0.003 to 1.000Ω
• Ideal for high current sensing applications
• Standard Sn/Pb and Pb-free (matte Sn) terminations available
Electrical Data
LRF3W Series
Environmental Data
Environmental Test Test Method Specification
Maximum Typical
Thermal Shock MIL-STD-202 Method 107
Condition F, -65°C to +150°C ±0.25% (+1.0mΩ) ±0.05% (+1.0mΩ)
Short-time Overload 5 Seconds, 3X Rated Power
Maximum 25 Amps ±0.50% (+0.5mΩ) ±0.01% (+0.5mΩ)
High Temperature Exposure MIL-PRF-55342
100 Hours, 150°C, No Power ±0.50% (+0.5mΩ) ±0.10% (+0.5mΩ)
Load Life 1000 Hours, 70°C, Rated Power ±1.00% (+0.5mΩ) ±0.20% (+0.5mΩ)
Moisture Resistance MIL-STD-202 Method 106 ±0.50% (+0.5mΩ) ±0.10% (+0.5mΩ)
Low Temperature Operation MIL-PRF-55342 ±0.25% (+0.5mΩ) ±0.05% (+0.5mΩ)
Resistance To Solder Heat MIL-STD-202 Method 210 ±0.25% (+1.0mΩ) ±0.05% (+1.0mΩ)
Solderability MIL-PRF-55342 ≥95% Coverage
IRC’s LRF3W-MIL series combines high power capabilities, small chip
size, very low resistance and high reliability to handle your current sens-
ing needs. The LRF3W-MIL utilizes high reliability thick film materials and the uninterrupted 2 pad termination
on the long sides maximizes the thermal trasport path, improving reliability. Precise measurements can be
achieved even at very low values using the specified kelvin pad layout (see Physical Data).
Resistance
Range(Ω)
Absolute
TCR
(ppm/°C)
Available Absolute
Tolerances
Rated Power
@ 70°C (W)
Voltage
Rating
(V)
Operating
Temperature
Range
Termination
0.003 - 0.005 ±500 ±10%
3.0* P x R -55°C to
+150°C
matte Sn or
60/40 Sn/Pb
0.006 - 0.009 ±250 ±5%, ±10%
0.010 - 1.000 ±100 ±1%, ±2%, ±5%, ±10%
*Note: 3-Watt rating achieved with 500mm2 Copper pad area around each termination pad. Maximum current is 25 amps.
√
LRF3W-MIL Series Issue April 2010
Advanced Film Division • 4222 South Staples Street • Corpus Christi Texas 78411 USA
Telephone: 361 992 7900 • Facsimile: 361 992 3377 • Website: www.irctt.com
Low Range 3 Watt
Mil Chip Resistor
Pulse Power Limit
1K
100
10
Pulse Width
Pulse Peak (Watts)
1ms 10ms 100ms 1000ms
200
100
10
Termination Pad Area (each end)
Temperature Rise (°C)
100m2 300mm2 1000m2
Temperature Rise vs Pad Area
1 watt 2 watts 3 watts
Damage Level
Safety Zone
LRF3W-MIL Series Issue April 2010
Advanced Film Division • 4222 South Staples Street • Corpus Christi Texas 78411 USA
Telephone: 361 992 7900 • Facsimile: 361 992 3377 • Website: www.irctt.com
Prefix LRC - LRF3WLF - MIL - R020 - F
Model
LRF3W = 3 watt chip with standard Sn/Pb termination
LRF3WLF = 3 watt chip with Pb-free (matte Sn) termination
MIL Designator
Resistance Code
4-Digit resistance code
Example: R050 = 0.050Ω; R005 = 0.005Ω
Tolerance Code
F = ±1%; G = ±2%; J = ±5%; K = ±10%
For additional information or to discuss your specific requirements,
please contact our Applications Team using the contact details below.
Power Derating Curve Ordering Data
Physical Data
Wrap-around
plating
0.030
thickness
BOTTOM
(Board Side)
0.125
TOP
0.020
SUGGESTED MEASUREMENT
LAYOUT
0.250
0.032
To achieve 3-Watt power rating,
the copper pad area of each
side must be a minimum of
500mm2 .
Protective Overcoat
Sn or Sn/Pb
Plating
Ni Barrier
Layer
Cu Plating
Conductor
Alumina
Substrate
"±.005
"±.005
"±.005
"±.005
"±.005
Overglaze
(Stability Enhancer)
High Reliability
Resistance
Element
0.280”
0.198”
0.075”
0.035”
0.173”
0.023”
0.010”
TYP. 0.015”
Current Sense
Traces
Low Range 3 Watt
Mil Chip Resistor
