USR UNR 4-3425
FEATURES
•
•
•
•
•
Resistances from 0.05Ohm to 500Ohms
Power Rating to 50Watt
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
USR 4-3425
UNR 4-3425
0.05 to 650 Ohms
other resistance values upon request / power rating depending
on resistance value
3W (available with heat sink on backside: 5W)
30W
50W
Tolerances
from 0.05 Ohms
from 10.0 Ohms
from 50.0 Ohms
Thermal Resistance
Stability (1000h)
Shelf Life Stability
Temperature Coefficient
Voltage Proof
Maximum Current
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%
3.5 K/W
2.1 K/W
0.01%
25ppm / ∆R after 1 year
50ppm / ∆R after 3 years
max. ±5ppm/K (-55 to 155°C)
typ. ±3ppm/K (-55 to 125°C)
typ. ±1ppm/K (25 to 60°C)
upon request ±1ppm/K (0 to 60°C)
750 VDC
15A
< 0.1µV/K
-55 to 155°C
NiCr-Foil
Al
2
O
3
Epoxy + Al-heatsink
Cu / tinned
4 (standard contact D)
1 Nm
Specially designed for ap-
plications with fast changing
electrical load
AlN
ORDERING INFORMATION
Part Number - Resistance - Contact - Tolerance - TCR (if not standard)
USR 4-3425 10R000 D 0.5% 1ppm/K (0 to 60°C)
Document No.: 64223
Revision: 03-05-2016
For technical questions,
contact
powertron@vpgsensors.com
www.powertron.de
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USR UNR 4-3425
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 -
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 :
Power (% from
nominal power)
120
100
80
60
40
20
0
25
50
85
100
115
130
145
155
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)
FIGURE 3—DIMENSIONS
in mm (inches)
Dimension
A
±2.0 (±0.079)
B
±0.3 (±0.012)
C
±0.2 (±0.008)
D
±0.2 (±0.008)
E
±0.1 (±0.004)
F
±0.2 (±0.008)
G
±0.1 (±0.004)
H
±0.1 (±0.004)
I
±0.2 (±0.008)
J
±0.2 (±0.008)
K
±0.1 (±0.004)
L
±0.1 (±0.004)
M
±0.2 (±0.008)
50.00 (1.97)
34.00 (1.34)
25.00 (0.98)
10.00 (0.39)
5.00 (0.20)
17.80 (0.70)
Ø3.50 (Ø0.14)
Ø0.8 (Ø0.031)
27.50 (1.08)
17.50 (0.69)
2.00 (0.08)
4.50 (0.18)
3.00 (0.12)
www.powertron.de
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For technical questions,
contact
powertron@vpgsensors.com
Document No.: 64223
Revision: 03-05-2016
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Revision: 15-Jul-2014
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