Ohmite LVK Series Data Sheet

LVK Series

Ambient Temperature (°C)

100

40

80

20

60

0

% Rated Power

+70°C -40°C

25 12575-25 0 50-50 100

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 cali­brated 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 pro­prietary 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.

SERIES SPECIFICATIONS

Power Resistance Max. Over Current

Pkg. Rating Range TCR Available Max. Max.

Series Size (W @70°C) (Ω) (ppm/°C) Tolerance Values Power Current

LVK12 1206 0.5W 0.01-0.100 50ppm 0.25%, 0.5%, 1% E12 20W 20A
LVK20 2010 0.75W 0.01-0.05 50ppm 0.25%, 0.5%, 1% E12 29W 23A
LVK24 2412 1.0W 0.01-0.100 50ppm 0.25%, 0.5%, 1% E12 38W 27A

0.001 300ppm

LVK25 1224 2.0W 0.002-0.004 200ppm

0.005-0.01 100ppm

0.25% 5 & 10mΩ

FEATURES

• Designedforautomaticinsertion

• Industrystandardsizes

• High-precisionKelvinconnectcapability

in a small package

1% 1, 2, 3, 5, 9,10mΩ

150W 200A

Res. Range

Operating Temp. Range

Rated Ambient Temperature

Resistance Tolerance

Temperature Coefficient

Coating Material

Terminals

Max. Over Current

Storage conditions

CHARACTERISTICS

0.001Ω - 0.010Ω

-40°C to +125°C
+70°C

0.25%, 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%

Derating

V = sensing terminal
(voltage)

I = current terminal

VV

II

LVK Series

Temperature °C

Time (sec.)

Preheating

130 ~ 180℃

60 ~ 90 sec.

Heating

Peak

200

50

300

250

100

150

Over 220℃

30s ~ 90s

240 ~ 260℃ Max. 10s

L

W

b

a

t

1

2

3

4

W

L

a

LVK 12, LVK20, LVK24 (0.5, 0.75 & 1 watt) LVK25 (2 watt)

Land Pattern

1. Electrode

2. Protection

coat

3. Almina
substrate

4. Resistor

t

b

g

d

f

e

Four Terminal High Precision Current Sense

PERFORMANCE CHARACTERISTICS

Test Items Performance Requirements Test Methods / standard: JIS C 5201.1

Overload

Endurance at 70°C

Moisture

resistance

Rapid change of

temperature

Resistance to sol-

dering heat

Substrate bending

Solderability

Reflow Temperature Profile

For lead free soldering (Sn-Ag-Cu solder)

±(0.5%+0.0005Ω) Rated voltage x 1.5 for 5s
±(0.5%+0.0005Ω) 70°C±3°C, Rated voltage 1.5h ON, 0.5h OFF, 1000h
±(0.5%+0.0005Ω) 60°C±2°C, 90%~95% RH, Rated voltage 1.5h ON,

±(0.5%+0.0005Ω) -40°C (30min.)/+125°C (30min.), 5 cycles

±(0.5%+0.0005Ω) 260°C±5°C for 10s±1s

±(0.5%+0.0005Ω) Bending width: 2mm for 10s±1s, Glass epoxy sub-

95% or more of the electrode surface
shall be covered with new solder

0.5h OFF, 1000h

strate with thickness of 1.6mm
245°C±5°C for 3s±0.5s

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

DIMENSIONS

(mm)

Note that LVK25 has a
vertical orientation with the
current flow along the short
edge of the resistor.

Size L W t a b d e f g
LVK12 (1206) 3.2 ±0.2 1.6 ±0.2 0.5 ±0.15 1.0 ±0.2 0.55 ±0.2 1.10 0.30 1.00 1.75
LVK20 (2010) 5.0 ±0.2 2.5 ±0.2 0.5 ±0.15 1.7 ±0.2 0.9 ±0.2 1.55 0.50 1.40 2.55
LVK24 (2412) 6.4 ±0.2 3.2 ±0.2 0.5 ±0.15 2.1 ±0.2 1.2 ±0.2 1.90 0.60 2.00 3.25
LVK25 (1224) 3.2 ±0.2 6.4 ±0.2 0.5 ±0.2 0.4 ±0.2 2.7 ±0.2 1.40 2.20 1.00 3.30

Schematic

Layout for illustration only, part
can be rotated 180° without
effect to the circuit: