USR UNR 4-T220B T221
FEATURES
•
•
•
•
•
Resistances from 0.2Ohm to 80Ohms
Power Rating to 15Watt
Resistance Tolerances to ±0.01%
TCR to ±1ppm/K
Load Stability to 0.01%
TABLE 1—SPECIFICATIONS
TYPE
Resistance Range
Power Rating
Free air 70°C
With heatsink
1.5W
10W
15W
USR 4-T220B
USR 4-T221
0.2 to 80 Ohms
UNR 4-T220B
UNR 4-T221
Tolerances
from 0.2 Ohms
from 10.0 Ohms
from 50.0 Ohms
Thermal Resistance
Stability (1000h)
Temperature Coefficient
Shelf Life Stability
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%
0.01% / 0.02% / 0.05% / 0.1% / 0.25% / 0.5% / 1%
10.8 K/W
6.8 K/W
0.01%
max. ±5ppm/K (-55 to 155°C)
typ. ±3ppm/K (-55 to 125°C)
upon request ±1ppm/K (25 to 60°C)
25ppm / ∆R after 1 year
50ppm / ∆R after 3 year
1 kVDC
< 0.1µV/K
-55 to 155°C
NiCr-Foil
Al
2
O
3
Cu / tinned
4
1 Nm
Specially designed for ap-
plications with fast changing
electrical load
AlN
Epoxy + Cu heatsink nickel plated
ORDERING INFORMATION
Part Number - Resistance - Contact - Tolerance - TCR (if not standard)
UNR 4-T220B 78R000 C 0.5%
UNR 4-T220B 15K000 S 0.5% 1ppm/K (25 to 60°C
Document No.: 64225
Revision: 31-01-2015
For technical questions,
contact
powertron@vpgsensors.com
www.powertron.de
1
USR UNR 4-T220B 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 heatsink.
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.: 64225
Revision: 31-01-2015
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