Low Range 3 Watt
Mil Chip Resistor
LRF3W Series
•
•
•
•
•
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
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).
Electrical Data
Resistance
Range(Ω)
0.003 - 0.005
0.006 - 0.009
0.010 - 1.000
Absolute
TCR
(ppm/°C)
±500
±250
±100
Available Absolute
Tolerances
±10%
±5%, ±10%
±1%, ±2%, ±5%, ±10%
3.0*
Rated Power
@ 70°C (W)
Voltage
Rating
(V)
Operating
Temperature
Range
-55°C to
+150°C
Termination
√
P x R
matte Sn or
60/40 Sn/Pb
*Note: 3-Watt rating achieved with 500mm
2
Copper pad area around each termination pad. Maximum current is 25 amps.
Environmental Data
Environmental Test
Thermal Shock
Short-time Overload
High Temperature Exposure
Load Life
Moisture Resistance
Low Temperature Operation
Resistance To Solder Heat
Solderability
Test Method
MIL-STD-202 Method 107
Condition F, -65°C to +150°C
5 Seconds, 3X Rated Power
Maximum 25 Amps
MIL-PRF-55342
100 Hours, 150°C, No Power
1000 Hours, 70°C, Rated Power
MIL-STD-202 Method 106
MIL-PRF-55342
MIL-STD-202 Method 210
MIL-PRF-55342
Specification
Maximum
±0.25% (+1.0mΩ)
±0.50% (+0.5mΩ)
±0.50% (+0.5mΩ)
±1.00% (+0.5mΩ)
±0.50% (+0.5mΩ)
±0.25% (+0.5mΩ)
±0.25% (+1.0mΩ)
Typical
±0.05% (+1.0mΩ)
±0.01% (+0.5mΩ)
±0.10% (+0.5mΩ)
±0.20% (+0.5mΩ)
±0.10% (+0.5mΩ)
±0.05% (+0.5mΩ)
±0.05% (+1.0mΩ)
≥95%
Coverage
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.
Advanced Film Division
• 4222 South Staples Street • Corpus Christi Texas 78411 USA
Telephone: 361 992 7900 • Facsimile: 361 992 3377 • Website: www.irctt.com
A subsidiary of
TT electronics plc
LRF3W-MIL Series Issue April 2010
Low Range 3 Watt
Mil Chip Resistor
Temperature Rise vs Pad Area
200
Temperature Rise (°C)
100
10
100m
2
1 watt
300mm
2
1000m
2
3 watts
Termination Pad Area (each end)
2 watts
Pulse Power Limit
1K
Pulse Peak (Watts)
Damage Level
100
Safety Zone
10
1ms
10ms
100ms
1000ms
Pulse Width
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
Physical Data
TOP
0.020
"±.005
BOTTOM
(Board Side)
SUGGESTED MEASUREMENT
LAYOUT
0.198”
Overglaze
(Stability Enhancer)
Protective Overcoat
0.075”
Sn or Sn/Pb
Plating
Ni Barrier
Layer
0.280”
0.035”
0.173”
0.125
"±.005
Wrap-around
plating
0.250
"±.005
High Reliability
Resistance
Element
Alumina
Substrate
Conductor
0.010”
TYP.
0.023”
0.015”
Current Sense
Traces
0.030
"±.005
thickness
0.032
"±.005
Cu Plating
To achieve 3-Watt power rating,
the copper pad area of each
side must be a minimum of
500mm
2
.
Power Derating Curve
Ordering Data
Prefix
Model
LRC
-
LRF3WLF
- MIL
- R020
-
F
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.
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
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