LVK Series
Four Terminal High Precision Current Sense
Current sense resistors enable the measurement of current flow
in a circuit by monitoring a voltage drop across a precisely cali-
brated resistance. The LVK chip features four terminals, also
known as a “Kelvin” configuration. This configuration enables
current to be applied through two opposite terminals and a
sensing voltage to be measured across the other two terminals,
eliminating the resistance and temperature coefficient of the
terminals for a more accurate current measurement.
Isolating the voltage and current terminals (see schematic)
facilitates a very accurate current measurement. Ohmite’s pro-
prietary technology offers an excellent Temperature Coefficient
of Resistance (TCR) even for very low resistance values. The
resistive element consists of a durable, anti-corrosive metal
alloy that combines reliable performance with the ability to
withstand harsh environments.
Power
Rating
(W @70°C)
0.5W
0.75W
1.0W
2.0W
Resistance
Range
(Ω)
0.01-0.100
0.01-0.05
0.01-0.100
0.001
0.002-0.004
0.005-0.01
F e at u r e S
• Designed for automatic insertion
• Industry standard sizes
• High-precision Kelvin connect capability
in a small package
S e r i e S S p e c i F i c at i o n S
Series
LVK12
LVK20
LVK24
LVK25
Pkg.
Size
1206
2010
2412
1224
TCR
(ppm/°C)
50ppm
50ppm
50ppm
300ppm
200ppm
100ppm
Tolerance
0.5%, 1%
0.5%, 1%
0.5%, 1%
1%
Available
Values
E12
E12
E12
Max. Over Current
Max.
Max.
Power
Current
20W
20A
29W
23A
38W
27A
150W
200A
1, 2, 3, 5, 9,10mΩ
characteriSticS
Res. Range
Operating Temp. Range
Rated Ambient Temperature
Resistance Tolerance
Temperature Coefficient
Coating Material
Terminals
Max. Over Current
Storage conditions
0.001Ω - 0.010Ω
-40°C to +125°C
+70°C
0.5% and 1% standard
LVK12, LVK20, LVK24:
50ppm standard
LVK25:
100ppm, 200ppm, or 300ppm based on
resistance value
epoxy resin
100% matte tin
Time applied: 10ms max.
Interval: 60sec min.
Max. over current = √(Max. power÷ Resistance
value) or max. current, whichever is smaller.
Temperature: 5°C ~ 35°C
Humidity: 25% ~ 70%
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1-866-9-OHMITE • Int’l 1-847-258-0300 • Fax 1-847-574-7522 • www.ohmite.com • info@ohmite.com
LVK Series
Test Items
Overload
Endurance at 70°C
Moisture
resistance
Rapid change of
temperature
Resistance to sol-
dering heat
Four Terminal High Precision Current Sense
perFormance characteriSticS
Performance Requirements
±(0.5%+0.0005Ω)
±(0.5%+0.0005Ω)
±(0.5%+0.0005Ω)
±(0.5%+0.0005Ω)
±(0.5%+0.0005Ω)
Test Methods / standard: JIS C 5201.1
Rated voltage x 1.5 for 5s
70°C±3°C, Rated voltage 1.5h ON, 0.5h OFF, 1000h
60°C±2°C, 90%~95% RH, Rated voltage 1.5h ON,
0.5h OFF, 1000h
-40°C (30min.)/+125°C (30min.), 5 cycles
260°C±5°C for 10s±1s
Substrate bending
±(0.5%+0.0005Ω)
Bending width: 2mm for 10s±1s, Glass epoxy sub-
strate with thickness of 1.6mm
Solderability
95% or more of the electrode surface 245°C±5°C for 3s±0.5s
shall be covered with new solder
Reflow Temperature Profile
For lead free soldering (Sn-Ag-Cu solder)
Preheating: 130° ~ 180° 60s ~ 90s
Heating: Over 220° 30s ~ 90s
Peak:
240° ~ 260° Max. 10s
Ramp-up rate:
max 3°C/sec.
Time above liquidous: 60 – 150 sec.
Ramp-down rate:
max 6°C/sec.
Max. number of reflow: 2
Temperature °C
300
250
200
150
100
50
Peak
240 ~ 260℃ Max. 10s
Preheating
130 ~ 180℃
60 ~ 90 sec.
Over 220℃
30s ~ 90s
Heating
Time (sec.)
dimenSionS
(mm)
LVK 12, LVK20, LVK24 (0.5, 0.75 & 1 watt)
L
2
W
4
b
a
3
1.
Electrode
2.
Protection
coat
1
3.
Almina
substrate
4.
Resistor
LVK25 (2 watt)
L
a
b
W
Schematic
V
V
I
I
V = sensing terminal
(voltage)
I = current terminal
Layout for illustra-
tion only, part can be
rotated 180° without
effect to the circuit.
t
d
g
f
Land Pattern
e
t
Note that LVK25 has a
vertical orientation with the
current flow along the short
edge of the resistor.
Size
LVK20
(2010)
LVK12
(1206)
L
5.0 ±0.2
3.2 ±0.2
W
2.5 ±0.2
1.6 ±0.2
t
0.5 ±0.15
0.5 ±0.2
0.5 ±0.15
a
1.0 ±0.2
2.1 ±0.2
1.7 ±0.2
b
0.55 ±0.2
1.2 ±0.2
0.9 ±0.2
d
1.55
1.10
e
0.50
0.30
f
1.40
1.00
g
2.55
1.75
LVK25
(1224)
LVK24
(2412)
3.2 ±0.2
6.4 ±0.2
6.4 ±0.2
3.2 ±0.2
0.5 ±0.15
0.4 ±0.2
2.7 ±0.2
1.40
1.90
2.20
0.60
1.00
2.00
3.30
3.25
1-866-9-OHMITE • Int’l 1-847-258-0300 • Fax 1-847-574-7522 • www.ohmite.com • info@ohmite.com
13
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