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 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. F e at u r e s • Designed for automatic insertion • Industry standard sizes • High-precision Kelvin connect capability in a small package Schematic V S e r i e s S p e c i f i c at i o n s Power ResistanceMax. 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 0.5%, 1% E12 20W 20A LVK20 2010 0.75W 0.01-0.05 50ppm 0.5%, 1% E12 29W 23A LVK24 2412 1.0W 0.01-0.100 50ppm 0.5%, 1% E12 38W 27A 0.001 300ppm LVK25 1224 2.0W 0.002-0.004 200ppm 1% 1, 2, 3, 5, 9,10mΩ 150W 200A 0.005-0.01 100ppm characteristics Res. Range Operating Temp. Range Rated Ambient Temperature Resistance Tolerance Temperature Coefficient Coating Material Terminals Max. Over Current Storage conditions 12 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% 1-866-9-OHMITE • Int’l 1-847-258-0300 • Fax 1-847-574-7522 • www.ohmite.com • [email protected] V I I V = sensing terminal (voltage) I = current terminal LVK Series Four Terminal High Precision Current Sense performance characteristics Test Items Overload Endurance at 70°C Moisture resistance Rapid change of temperature Resistance to soldering heat Performance Requirements ±(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 ±(0.5%+0.0005Ω) 260°C±5°C for 10s±1s Substrate bending ±(0.5%+0.0005Ω) Bending width: 2mm for 10s±1s, Glass epoxy substrate 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: Time above liquidous: Ramp-down rate: Max. number of reflow: Temperature °C 300 max 3°C/sec. 60 – 150 sec. max 6°C/sec. 2 250 200 150 100 50 dimensions (mm) L LVK25 (2 watt) W LVK 12, LVK20, LVK24 (0.5, 0.75 & 1 watt) L 2 W a 4 b Size LVK12 (1206) LVK20 (2010) LVK24 (2412) LVK25 (1224) t t 3 a 1 b 1. Electrode 2. Protection coat 3. Almina substrate 4. Resistor L W t a b 3.2 ±0.2 1.6 ±0.2 0.5 ±0.15 1.0 ±0.2 0.55 ±0.2 2.1 ±0.2 1.2 ±0.2 5.0 ±0.2 6.4 ±0.2 3.2 ±0.2 2.5 ±0.2 3.2 ±0.2 6.4 ±0.2 0.5 ±0.15 0.5 ±0.15 0.5 ±0.2 1.7 ±0.2 0.4 ±0.2 1-866-9-OHMITE • Int’l 1-847-258-0300 • Fax 1-847-574-7522 • www.ohmite.com • [email protected] 0.9 ±0.2 2.7 ±0.2 13 Peak 240 ~ 260℃ Max. 10s Heating Preheating Over 220℃ 30s ~ 90s 130 ~ 180℃ 60 ~ 90 sec. Time (sec.) LVK Series Four Terminal High Precision Current Sense dimensions (mm, continued) Land Pattern Reel LVK25 (1224) L A 13mm ±0.3 (LVK12) 15mm ±0.3 (LVK 20, 24, 25) 2mm ±0.5 13mm ±�0.2 W 180mm ±3 Series LVK12 LVK20 LVK24 LVK25 L W A B 60mm ±1 B 1.75 1.10 1.00 0.30 2.55 1.55 1.40 0.50 3.25 1.90 2.00 0.60 9mm ±0.3 (LVK12) 13mm ±0.3 (LVK 20, 24, 25) 1.40 3.30 2.20 1.00 Tape P0 T D0 Direction of feed P2 A B E W F B W F E P0 D1 T2 P1 A P1 P2 D0 D1 T T2 LVK12 LVK20 LVK24 LVK25 1.90 ±0.10 2.90 ±0.1 3.43 ±0.2 3.43 ±0.2 8.0 ±0.2 12.0 ±0.2 12.0 ±0.3 12.0 ±0.3 3.50 ±0.10 3.5 ±0.05 1.75 ±0.1 4.0 ±0.1 4.0 ±0.1 2.0 ±0.05 5.35 ±0.1 5.5 ±0.05 1.75 ±0.1 4.0 ±0.1 4.0 ±0.1 2.0 ±0.05 6.63 ±0.2 5.5 ±0.05 1.75 ±0.1 4.0 ±0.1 4.0 ±0.1 2.0 ±0.05 6.63 ±0.2 5.5 ±0.05 1.75 ±0.1 4.0 ±0.1 4.0 ±0.1 2.0 ±0.05 1.5 +0.1/-0 1.5 +0.1/-0 1.5 +0.1/-0 1.5 +0.1/-0 0.2 ±0.05 0.2 ±0.05 0.2 ±0.05 0.2 ±0.05 1.0 +0.20/-0 1.0 ±0.2 1.5 +0.2/-0 1.0 ±0.2 1.5 +0.2/-0 1.0 ±0.2 1.5 +0.2/-0 1.0 ±0.2 ORDERIN G IN F ORMATION RoHS Compliant LVK25R005FER Series 14 Case Size 12 = 1206 20 = 2010 24 = 2412 25 = 1224 Tolerance Taping Code Ohms R005 = 0.005 D = 0.5% R = 1,000 pc/reel F = 1% Standard values LVK12 LVK20 LVK24 1% Tolerance 0.01 0.01 0.01 0.012 0.012 0.015 0.015 0.02 0.02 0.02 0.024 0.027 0.025 0.03 0.03 0.03 0.033 0.033 0.039 0.039 0.039 0.047 0.047 0.05 0.05 0.05 0.075 0.075 0.10 0.10 LVK25 0.001 0.002 0.003 0.005 0.01 1-866-9-OHMITE • Int’l 1-847-258-0300 • Fax 1-847-574-7522 • www.ohmite.com • [email protected] LVK12 LVK20 LVK24 0.5% Tolerance 0.01 0.01 0.01 0.015 0.015 0.02 0.02 0.02 0.025 0.025 0.03 0.03 0.03 0.033 0.033 0.039 0.05 0.05 0.05 0.075 0.10 0.10 LVK25 0.001 0.002 0.003 0.005 0.010