USR UNR 2-T220 T221
FEATURES
•
•
•
•
•
•
Resistances from 0.5Ohm to 150kOhms
Power Rating to 10Watt
Resistance Tolerances to ±0.01%
TCR to ±3ppm/K
Load Stability to 0.01%
TO-220 Housing
TABLE 1—SPECIFICATIONS
TYPE
Resistance Range
Free air 70°C
R < 50R0
R > 50R0
With heatsink
R < 50R0
R > 50R0
USR 2-T220
USR 2-T221
0.5 Ohms to 150 kOhms
1.5W
1.0W
10W
6W
UNR 2-T220
UNR 2-T221
0.5 Ohms to 5 kOhms
1.5W
1.0W
15W
10W
Power Rating
Tolerances
from 0.5 Ohms
from 10.0 Ohms
from 25.0 Ohms
from 50.0 Ohms
Thermal Resistance Rthj-c
R<50R0
R>50R0
Stability (1000h)
Shelf Lifw Stability
Temperature Coefficient
Voltage Proof
Thermal EMF
Operating Temperature Range
Resistor Material
Substrate
Housing
Connector Material
Terminals
Max. Torque
Notes
0.1% / 0.25% / 0.5% / 1%
0.05% / 0.1% / 0.25% / 0.5% / 1%
0.02% / 0.05% / 0.1% / 0.25% / 0.5% / 1%
0.01% / 0.02% / 0.05% / 0.1% / 0.25% / 0.5% / 1%
10.8 K/W
18.8 K/W
0.01%
25ppm / ∆R after 1 year
50ppm / ∆R after 3 year
max. ±5ppm/K (-55 to 155°C)
typ. ±3ppm/K (-55 to 125°C)
1 kVDC
< 0.1µV/K
-55 to 155°C
NiCr-Foil
Al
2
O
3
Cu / tinned
2
1.0 Nm
Specially designed for ap-
plications with fast changing
electrical load
AlN
Epoxy + Cu heatsink nickel plated
6.8 K/W
10.8 K/W
ORDERING INFORMATION
Part Number - Resistance - Contact - Tolerance - TCR (if not standard)
UNR 2-T220B 4K700 C 0.5%
Document No.: 64222
Revision: 31-01-2015
For technical questions,
contact
powertron@vpgsensors.com
www.powertron.de
1
USR UNR 2-T220 T221
FIGURE 1—TEMPERATURE COEFFICIENT
200
100
0
∆R/R
(ppm)
-100
-200
-300
-400
-500
-600
-700
-75
-50
-25
0
25
50
Temperature (°C)
75
100
125
Nominal Spread
±2.3ppm/K
150
Nominal
∆R/R
Nominal Spread
±2.3ppm/K
FIGURE 2—DERATING
Power Rating Notes -
Power (% from
nominal power)
120
100
80
60
40
20
0
25
50
85
100
115
130
145
155
The U-Series Resistors must be attached to a suitable heat-
sink. The maximum internal resistor temperature is 155°C.
To specify an appropriate heatsink use the following formula :
R
qH
= T
MAX
- ( P x R
qR
) - T
A
P
Where:
R
qH
= Thermal Resistance of Heatsink ( K/W )
R
qR
= Thermal Resistance of Resistor ( K/W )
T
MAX
= Maximum Temperature of Resistor
T
A
= Ambient Temperature of Heatsink ( °C )
P = Power Through Resistor ( W )
Temperature of the backplate(°C)
www.powertron.de
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For technical questions,
contact
powertron@vpgsensors.com
Document No.: 64222
Revision: 31-01-2015
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Vishay Precision Group, Inc.
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Document No.: 63999
Revision: 15-Jul-2014
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