OARS3R005FLF Datasheet, PDF (2/4 Pages) IRC - a TT electronics Company. – Open Air Sense Resistors Metal Alloy Strip

OARS-3
Open Air Sense Resistors
Metal Alloy Strip
Environmental Data
Test Spec: AEC Q200
TCR +125 to -55°C
Thermal Shock
High Temperature Exposure 125°C
Temperature Cycling: -40 to +125°C
Operational Life
Baised Humidity
Mechanical Shock
Vibration
Moisture Resistance
Terminal Strength
Solvent Resistance
Solderability
Power Derating Curve
3.5
3.0
2.5
2.0
1.0
0.0
25
60
95
130
165
Ambient Temperature (°C)
2m - 3m
4m - 15m
240ppm
40ppm
<0.75%
<0.75%
<1.75%
<0.5%
<1.0%
<1.0%
<2.0%
<1.0%
<0.75%
<0.5%
<1.5%
<1.0%
<1.0%
<1.0%
<1.0
<2.5%
Meets JIS-C-6429
Meets MIL-STD-202 Method 215
Meets J-STD-002 Method B
Note:
The power derating curve is a guidance based on a con-
servative design model. The OARS is a solid metal alloy
construction that can withstand significantly greater operating
temperatures than conservative design models permit. The
resistive alloys can withstand temperatures in exess of 350°C.
Therefore, the system thermal design is a more significant
design parameter due to the heat limitations of solder joints
and/or circuit board substrate materials. Refer to additional
information below.
195
225
OARS R005 Thermal Image @ 4 Watts
Ambient conditions, No forced air.
The thermal image (not a simulation) to the left is of an OARS
5 mΩ running at 4 Watts, which exceeds the 1 Watt conserva-
tive model. Notice the hotpsot is nearly 230°C, but the solder
joint is approximately 110°C (FR4 is rated for 130°C). The
unique construction of the OARS isolates the hotspot from
the circuit board material preventing damage. Additionally,
the thermal energy is dissipated to the air instead of being
conducted into the circuit board potentially causing a nearby
power component to exceed its rating.
The standard test circuit board consists of a four layer FR4
material with 2 ounce outer layers and 1 ounce inner layers,
which is typical of many industry designs. Contact IRC for
more details or for other thermal image test data for specific
resistance values and power levels.
Wire and Film Technologies Division • 4222 South Staples Street • Corpus Christi Texas 78411 USA
Telephone: [phone] • Facsimile: 361 992 3377 • Website: www.irctt.com
February 2009 Issue Page 2 of 4