USR UNR USS UNS T220 T221
Powertron
•
•
•
•
•
•
•
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
Convenient SMD D2Pak Available
SPECIFICATIONS
Type
Resistance Range
Power rating
free air 70°C (R<50R0)
free air 70°C (R>50R0)
with heatsink (R<50R0)
with heatsink (R>50R0)
Thermal Resistance Rthj-c
R<50R0
R>50R0
Tolerances
from 0.5 Ohms
from 10.0 Ohms
from 25.0 Ohms
from 50.0 Ohms
Stability
Shelf Life Stability
Temperature Coefficient
Voltage Proof
Thermal EMF
Operating Temperature Range
Resistor Material
Substrate
Housing
Connector Material
Terminals
Max. Torque
Notes
Al
2
O
3
Epoxy + Cu heatsink nickel plated
Cu tinned
2
1.0 Nm
Specially designed for applications with fast
changing electrical load
USR / USS
0.5 Ohms to 150 kOhms
1.5W
1.0W
10W
6W
10.8 K/W
18.8 K/W
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%
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
UNR /UNS
0.5 Ohms to 5 kOhms
1.5W
1.0W
15W
10W
6.8 K/W
10.8 K/W
AlN
Ordering Information
Part Number - Resistance - Contact - Tolerance - TCR
UNR 2-T220B 5.7kOhms C 0.5% 3ppm
Document Number: 64222
Revision: 20-09-10
For technical questions, contact:
powertron@vishaypg.com
www.powertron.de
1
USR UNR USS UNS T220 T221
Powertron
SPECIFICATIONS
(continued)
Temperature Coefficient
1500
1000
-5ppm/K
+5ppm/K
500
DR/R
(ppm)
0
+4,4 ppm/K
Nominal Spread
±2.3ppm/K
Nominal
DR/R
Nominal Spread
±2.3ppm/K
-500
-1000
-1500
-50
-25
0
50
25
Temperature (°C)
75
100
125
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)
Dimensions
USS 2-T220 / UNS 2-T220
Dimension
A
B
C
D
E
F
G
H
I
J
K
mm
12.70
10.16
0.76
5.08
4.00
1.20
14.60
15.00
17.33
0.40
1.85
tol.
(±mm)
0.2
0.2
0.1
0.1
0.1
0.1
0.2
0.2
0.2
0.1
0.1
inches
0.50
0.40
0.03
0.20
0.16
0.05
0.57
0.59
0.68
0.02
0.07
tol.
(±inches)
0.008
0.008
0.004
0.004
0.004
0.004
0.008
0.008
0.008
0.004
0.004
Dimension
A
B
C
D
E
F
mm
12.10
11.16
18.33
5.08
1.76
3.20
inches
0.476
0.439
0.722
0.200
0.069
0.126
www.powertron.de
2
For technical questions, contact:
powertron@vishaypg.com
Document Number: 64222
Revision: 20-09-10
Legal Disclaimer Notice
Vishay Precision Group
Disclaimer
ALL PRODUCTS, PRODUCT SPECIFICATIONS AND DATA ARE SUBJECT TO CHANGE WITHOUT NOTICE.
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behalf (collectively, “Vishay Precision Group”), disclaim any and all liability for any errors, inaccuracies or
incompleteness contained herein or in any other disclosure relating to any product.
The product specifications do not expand or otherwise modify Vishay Precision Group’s terms and conditions of
purchase, including but not limited to, the warranty expressed therein.
Vishay Precision Group makes no warranty, representation or guarantee other than as set forth in the terms
and conditions of purchase.
To the maximum extent permitted by applicable law, Vishay Precision Group
disclaims (i) any and all liability arising out of the application or use of any product, (ii) any and all liability,
including without limitation special, consequential or incidental damages, and (iii) any and all implied
warranties, including warranties of fitness for particular purpose, non-infringement and merchantability.
Information provided in datasheets and/or specifications may vary from actual results in different applications
and performance may vary over time. Statements regarding the suitability of products for certain types of
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properties described in the product specification is suitable for use in a particular application.
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Document No.: 63999
Revision: 27-Apr-11
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