Metal Strip Current Sense
Resistors Surface Mount
ULR Series
Welwyn Components
•
•
•
•
•
1 watt to 3 watts, all 2512 size
Resistance R0005 (0.5mΩ) to R01 (10mΩ)
Low TCR, Low inductance
Designed for current sensing in
power electronic systems
RoHS compliant
Electrical Data
ULR1
Power rating at 80°C
Resistance range
Isolation voltage
TCR
Resistance Tolerance
Protective coating
Standard Values
Ambient temperature range
°C
2
1
ULR2
2.0
R0005 to R01
200V
50
1(F), 5(J)
ULR25
2.5
R0035 to R006
200V
50
ULR3
3.0
R0005 to R003
200V
50, 75, 100
See table below
watts
ohms
volts
ppm/°C
%
1.0
R0005 to R007
200V
50, 75, 100, 150
See table below
Black
Green/ Black
Green
Green
See table below for available values
-55 to +170
Note 1: For values above 0R01 refer to our LR / LRF Series
Note 2: Colour of coating relates to solder process suitability, see Construction
Standard Values Available
ULR1
Value
R0005
R00075
R001
R0015
R002
R0025
R003
R0035
R004
R0045
R005
R0055
R006
R007
R008
R009
R01
Colour
Black
Black
Black
Black
Black
Black
Black
Black
Black
Black
Black
Black
Black
Black
TCR
50
50
50
50
50
150
150
150
100
100
100
100
75
75
(non-standard values may be available to order - consult factory)
ULR2
Colour
Black
Black
Black
Black
Black
TCR
50
50
50
50
50
Colour
ULR25
TCR
Colour
Green
Green
Green
Green
Green
Green
Green
Green
Green
Green
Green
Green
Green
Green
Green
Green
Green
50
50
50
50
50
50
50
50
50
50
ULR3
TCR
100
100
50
50
50
75
75
General Note
Welwyn Components reserves the right to make changes in product specification without notice or liability.
All information is subject to Welwyn’s own data and is considered accurate at time of going to print.
A subsidiary of
TT electronics plc
Issue A · 09.06
© Welwyn Components Limited
· Bedlington, Northumberland NE22 7AA, UK
Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com
Metal Strip Current Sense
Resistors Surface Mount
ULR Series
Welwyn Components
Construction
Black type
A low TCR resistance alloy plate, with plated connection bands is
protectively coated and numerically marked with the resistance value.
This part has standard plated end connections and is suitable for wave
or IR reflow soldering.
Green type
A low TCR resistance alloy plate is grooved to set the final resistance,
the lower faces are solder plated for connections, and it is protectively
coated and numerically marked with the resistance value. This part is
ONLY suitable for IR reflow soldering.
Sn Plated Finish
Cn Plating
Protective Coating
Ally Plate
Black Type
Protective Coating
Metal Strip
Marking
For values which are integer numbers of milliohms, the marking is
4-character IEC62 code; e.g. “R002” for 2mΩ, “R010” for 10mΩ.
For values including fractions of a milliohm the marking is 3 or 4-
character code using “M” to indicate the decimal point, e.g. “M75”
for 0.75mΩ, “1M50” for 1.5mΩ.
Sn Plated Finish
Green Type
Termination Details:
Material
Matt tin plated finish over a barrier layer
Solderability
95% min coverage (MIL-STD 202F / 208H, 235ºC 2 secs)
Performance Data
Maximum
Load at rated power
(1000hrs cyclic load at 70°C)
De-rating from rated power at 80°C
Short term overload
(5 x rated power for 5s)
Dry heat
(96Hrs, no load, +155°C)
Temperature rapid change
(-55 / +150ºC, 100 cycles)
Resistance to solder heat
(260ºC for 10s)
∆R%
∆R%
∆R%
∆R%
∆R%
±1% + 0.5mΩ (Black): ±1% (Green)
See Graph
±0.5% + 0.5mΩ (Black): ±1% (Green)
±1% + 0.5mΩ (Black): ±1% (Green)
±0.5% + 0.5mΩ (Black): ±1% (Green)
±0.5% + 0.5mΩ (Black): ±1% (Green)
Power de-rating graph
P
100%
50%
T°C
0%
-55
0
80
170
© Welwyn Components Limited
Bedlington, Northumberland NE22 7AA, UK
Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com
Issue A · 09.06
Metal Strip Current Sense
Resistors Surface Mount
ULR Series
Welwyn Components
Recommended Solder Pad Layout
1.8
4.75
1.45
0.7
3.6
1.8
4.75
4-wire pad layout (recommended for precision current sensing)
2-wire pad layout
Dimensions (mm)
Type
Green
Green
Black
Black
Black
Black
Black
Black
Black
Black
Black
Black
Black
Black
Black
Black
Values (mΩ)
0.5mΩ, 0.75mΩ
1mΩ to 10mΩ
0.5mΩ
0.75mΩ
1mΩ
1.5mΩ
2mΩ
2.5mΩ
3mΩ
3.5mΩ
4mΩ
4.5mΩ
5mΩ
5.5mΩ
6mΩ
7mΩ
L
6.35
6.35
6.35
6.35
6.35
6.35
6.35
6.35
6.35
6.35
6.35
6.35
6.35
6.35
6.35
6.35
W
3.18
3.18
3.18
3.18
3.18
3.18
3.18
3.18
3.18
3.18
3.18
3.18
3.18
3.18
3.18
3.18
T
1.00
0.60
1.40
1.00
0.80
0.65
0.50
1.00
0.70
0.71
0.60
0.58
0.50
0.47
0.50
0.45
D
1.93
1.93
1.30
1.30
1.30
1.30
1.30
1.30
1.30
1.30
1.30
1.30
1.30
1.30
1.30
1.30
Nom. Wt. (g)
0.09
0.08
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
T
L
W
D
Flammability
The resistor will not burn or emit incandescent particles under any condition of applied temperature or overload.
Solvent resistance
The body protection and marking are resistant to all normal industrial solvents suitable for printed circuits.
Packaging
The standard packing for ULR parts is on a 2000 piece reel of size 12mm tape
Ordering Procedure
Example: ULR2 at 2.5 milliohms and 1% tolerance on reel of 2000 pieces:
Type
Resistance value (IEC62 code)
Tolerance (IEC62 code)
F
J
1%
5%
T2
Tape
2512
ULR2
- R0025
F
T2
Packing
2000 / reel
© Welwyn Components Limited
Bedlington, Northumberland NE22 7AA, UK
Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com
Issue A · 09.06
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