Low Resistance Metal
Low
Resistance Metal
Resistance Metal
Element Resistors
Element Resistors
Element Resistors
LOB
LOB Series
Series
LOB Series
•
low resistance values
Ultra
Ultra low resistance values
•
Ultra low resistance values
(0.005Ω to
(0.005Ω to 0.1Ω)
0.1Ω)
(0.005Ω
in 1,
0.1Ω)
5
and 5
rated
rated packages
to
in 1,
•
Available
3 and
3
watt
watt
packages
Available
•
Available in 1, 3 from5±1% to ±5%packages
Tolerances from ±1% to ±5%
•
Tolerances and watt rated
•
Tolerances
non-inductive
±5% (≤.02µH at 0.5MHz)
Inherently
from non-inductive
•
Inherently ±1% to
(≤.02μH at 0.5MHz)
Low temperature coefficient of resistance
•
Inherentlytemperature coefficientat 0.5MHz)
•
Low non-inductive (≤.02µH of resistance
High stability over life
•
Low temperature coefficient of resistance
•
High stability over life
•
High stability over life
Welwyn Components
Welwyn Components
·
·
·
·
·
·
Electrical Data
Electrical Data
Continuous power dissipation at 25°C in free air
Continuous power dissipation seconds in free air
Overload power for 5 at 25°C
Overload power for 5 seconds
Maximum working voltage
Maximum workingstorage temperature
Maximum voltage
watts
watts
volts
watts
LOB-1
watts
volts
°C
1
5
√1xR
LOB-1
1
5
√1xR
175
LOB-3
3
15
√3xR
LOB-3
3
15
√3xR
175
LOB-5
5
25
√5xR
LOB-5
5
25
√5xR
175
Maximum storage temperature
°C
175
175
* Power Dissipation - The maximum wattage rating depends upon the amount of heat which
175
be transferred to the surroundings while not exceeding the maximum element
can
temperature. Ambient air temperature, velocity of cooling air, thermal resistance of heat and the temperature of surrounding objects will affect this transfer, this must be taken
* Power Dissipation - The maximum wattage rating depends upon the amount of heat which can be transferred to the surroundings while not exceeding the maximum element
into account when selecting a resistor.
temperature. Ambient air temperature, velocity of cooling air, thermal resistance of heat and the temperature of surrounding objects will affect this transfer, this must be taken
into account when selecting a resistor.
Physical Data
Physical Data
Dimensions (mm)
Dimensions (mm)
Type
L max.
Type
contact point
D max.
f min.
d nom.
C
33.27
C
C
contact point
contact point
contact point
L max.
D
f min. 38.1±3.2 0.813±0.05
d nom.
C
LOB-1
9.9±0.3max. 3.6±0.2
LOB-1 LOB-3
14.22±0.25 5.33±0.25 34.93±3.18 0.81±0.05
9.9±0.3
3.6±0.2
38.1±3.2 0.813±0.05
33.27 33.27
LOB-3
14.22±0.25 5.33±0.25 34.93±3.18 0.81±0.05
33.27 42.42
LOB-5
23.37±0.25 8.38±0.25 31.75±3.18 1.02±0.05
LOB-5
23.37±0.25 8.38±0.25 31.75±3.18 1.02±0.05
42.42
d
d
D
D
L
L
f
f
Description
Construction
LOBΩ Series power precision metal element resistors feature
LOBΩ Series
Description
Construction
resistors feature tinned copper leads welded
resistance values down to 0.005Ω with virtually no
directly to a low temperature coefficient resistance
LOBΩ Series power precision metal element resistors feature
LOBΩ Series resistors feature tinned copper leads welded element in
inductance. Available in 1, with 5 watt no
resistance values down to 0.005Ω 3 andvirtually rated axial leaded directly a highly automated proprietary process. Theelement resistor
to a low temperature coefficient resistance leaded in
packages, these 1, 3 and 5 compatible with automatic a highly automated proprietary process.in a moulding compound.
elements are then encapsulated The leaded resistor
inductance. Available in resistors arewatt rated axial leaded
insertion resistors are
packages, these equipment. compatible with automatic
elements are then encapsulated in a moulding compound.
insertion equipment.
Applications
Applications
•
Switchmode and linear power supplies.
•
•
•
Switchmode and linear power supplies.
•
Automotive current-sensing circuits.
Automotive current-sensing circuits.
Instrumentation.
Instrumentation.
•
General Note
General
Note
Note
General
All information is subject to Welwyn’s own data and is considered accurate at time of going to print.
Welwyn Components reserves the right to make changes in product specification without notice or liability.
A subsidiary of
Welwyn Components reserves the right to make changes in product specification without notice or liability.
TT electronics plc
TT electronics reserves the right to make changes in product specification without notice or liability.
A subsidiary of
All information is subject to Welwyn’s own data and is considered accurate at time of going to print.
© Welwyn Components Limited
· Bedlington, Northumberland NE22 7AA, UK
All information is subject to TT electronics’ own data and is considered accurate at time of going to print.
TT electronics plc
www.bitechnologies.com
Issue
Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com
www.irctt.com www.welwyn-tt.com
B · 03.02
© Welwyn Components Limited
· Bedlington, Northumberland NE22 7AA, UK
Issue B · 03.02
Telephone: +44 (0) 1670
© TT electronics plc
822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com
104
104
11. 11
Low Resistance Metal
Low Resistance Metal
Element Resistors
Element Resistors
LOB Series
LOB Series
Power derating percentage vs
Free air ambient temperature
100
90
80
70
60
50
40
30
20
10
0
0
25
50
75
100
125
150
175
Welwyn Components
Temperature coefficient of resistance vs
Resistance value
Temperature Coefficient
of resistance (ppm/°C)
400
Rated Power (%)
300
200
100
0
0
25
50
75
100
Ambient Temp (°C)
Resistance (ohms x 10
-3
)
Test
Load life (2000 hours)
Thermal shock
Vibration
Mechanical shock
Dielectric strength
Insulation resistance
*±0.0005 ohm allowance for test/contact error.
MIL-STD 202
Method 108
Method 107
Method 204
Method 213
Method 301
Method 302
MAX %
∆
R*
±1%
±1%
±0.5%
±0.5%
±0.5%
>10
11
Unit
%
∆R
%
∆R
%
∆R
%
∆R
%
∆R
ohms
Packaging
Resistors are supplied taped and reeled.
Bulk packaging available.
Ordering Procedure
Example: LOB3 at 10 milliohms and 5% tolerance on a reel of 1250 pieces -
LOB3
–
R01J
I
Type
Value (use IEC62 code)
Tolerance (use IEC62 code)
F
H
Note: 1% & 5% preferred
1%
3%
J
5%
Packing
I
Tape
LOB1
LOB3
LOB5
3500/reel
1250/reel
800/reel
Standard
General Note
TT electronics reserves the right to make changes in product specification without notice or liability.
All information is subject to TT electronics’ own data and is considered accurate at time of going to print.
www.bitechnologies.com www.irctt.com www.welwyn-tt.com
© Welwyn Components Limited
Bedlington, Northumberland NE22 7AA, UK
Issue B · 03.02
Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com
© TT electronics plc
11. 11
105
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