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) FeatureS facilitates a very accurate current measurement. Ohmites pro- Designed for automatic insertion prietary technology offers an excellent Temperature Coefficient of Resistance (TCR) even for very low resistance values. The Industr y standard sizes resistive element consists of a durable, anti-corrosive metal High-precision Kelvin connect capability alloy that combines reliable performance with the ability to in a small package withstand harsh environments. SerieS SpeciFicationS Power Resistance Max. Over Current Pkg. Rating Range TCR Available Max. Max. Series Size (W 70C) () (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 1% 1, 2, 3, 5, 9,10m LVK25 1224 2.0W 0.002-0.004 200ppm 150W 200A 0.25% 5 & 10m 0.005-0.01 100ppm characteriSticS Res. Range 0.001 - 0.010 Derating Operating Temp. Range -40C to +125C 100 +70C Rated Ambient Temperature -40C +70C 80 Resistance Tolerance 0.25%, 0.5% and 1% standard Temperature Coefficient LVK12, LVK20, LVK24: 50ppm standard 60 LVK25: 100ppm, 200ppm, or 300ppm based on 40 resistance value 20 Coating Material epoxy resin 0 -50 -25 0 25 50 75 100 125 100% matte tin Terminals Ambient Temperature (C) Max. Over Current Time applied: 10ms max. Interval: 60sec min. Max. over current = (Max. power Resistance value) or max. current, whichever is smaller. Storage conditions Temperature: 5C ~ 35C Humidity: 25% ~ 70% 12 1-866-9-OHMITE Intl 1-847-258-0300 Fax 1-847-574-7522 www.ohmite.com info ohmite.com % Rated PowerLVK Series Four Terminal High Precision Current Sense perFormance characteriSticS Test Items Performance Requirements Test Methods / standard: JIS C 5201.1 (0.5%+0.0005) Rated voltage x 1.5 for 5s Overload Endurance at 70C (0.5%+0.0005) 70C3C, Rated voltage 1.5h ON, 0.5h OFF, 1000h Moisture (0.5%+0.0005) 60C2C, 90%~95% RH, Rated voltage 1.5h ON, resistance 0.5h OFF, 1000h (0.5%+0.0005) -40C (30min.)/+125C (30min.), 5 cycles Rapid change of temperature Resistance to sol- (0.5%+0.0005) 260C5C for 10s1s dering heat Substrate bending (0.5%+0.0005) Bending width: 2mm for 10s1s, Glass epoxy sub- strate with thickness of 1.6mm Solderability 95% or more of the electrode surface 245C5C for 3s0.5s shall be covered with new solder Reflow Temperature Profile 300 For lead free soldering (Sn-Ag-Cu solder) Peak 240 ~ 260 Max. 10s 250 Preheating: 130 ~ 180 60s ~ 90s Ramp-up rate: max 3C/sec. 200 Heating: Over 220 30s ~ 90s Time above liquidous: 60 150 sec. Heating Peak: 240 ~ 260 Max. 10s Ramp-down rate: max 6C/sec. 150 Over 220 30s ~ 90s Preheating Max. number of reflow: 2 100 130 ~ 180 60 ~ 90 sec. 50 Time (sec.) dimenSionS (mm) Schematic LVK 12, LVK20, LVK24 (0.5, 0.75 & 1 watt) LVK25 (2 watt) VV L 3 a L a 1. Electrode II 2. Protection b V = sensing terminal 2 coat (voltage) b 1 W 3. Almina I = current terminal substrate W Layout for illustration only, part 4. Resistor 4 can be rotated 180 without effect to the circuit: t g f d t Land Pattern e 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 1-866-9-OHMITE Intl 1-847-258-0300 Fax 1-847-574-7522 www.ohmite.com info ohmite.com 13 Temperature C