LPS 300 www.vishay.com Vishay Sfernice Power Resistor for Mounting onto a Heatsink Thick Film Technology FEATURES High power 300 W at 85 C bottom case temperature Wide resistance range: 0.3 to 900 k E24 series Non inductive Easy mounting Low thermal radiation of the case Material categorization: for definitions of compliance click logo to get started DESIGN SUPPORT TOOLS please see www.vishay.com/doc 99912 Models Available DIMENSIONS in millimeters 25.8 1 LPS 300 25.2 6K8 5 % 21.2 V2 60 15.2 0.5 36 64.7 2 x M4 useful depth: 8 2 x 4.2 20 13.6 34 57 Note Tolerances unless stated: 0.2 mm STANDARD ELECTRICAL SPECIFICATIONS RESISTANCE RATED POWER LIMITING ELEMENT TEMPERATURE CRITICAL TOLERANCE MODEL RANGE P VOLTAGE U COEFFICIENT RESISTANCE 85 C L % W V ppm/C () LPS 300 0.3 to 900K 300 5K 1, 2, 5, 10 150, 300, 500 83.33K MECHANICAL SPECIFICATIONS TECHNICAL SPECIFICATIONS 300 W at + 85 C Mechanical Protection Insulated case UL 94 V-0 Power Rating and bottom case temperature Resistive Element Thick film Thermal Resistance R : 0.112 C/W TH (j - c) Substrate Alumina Temperature Coefficient R 1 : 500 ppm/C End Connections Screws M4 1 < R 10 : 300 ppm/C -55 C / 120 C Standard 10 < R: 150 ppm/C IEC 60115-1 Tightening Torque 2 Nm Connections Dielectric Strength IEC 60115-1, 1 min, 7 kV or 12 kV RMS RMS Tightening Torque Heatsink 2 Nm 10 mA max. Maximum Torque 2.5 Nm Lightning test 1.2/50 s Until 12 kV Weight 83 g 10 % IEC 61000-4-5 4 Insulation Resistance 10 M ENVIRONMENTAL SPECIFICATIONS Inductance 0.1 H 100 pC/7 kV Temperature Range -55 C to 120 C Partial Discharge 10 pC/5 kV Climatic Category 55/120/56 (for LPS 300 D only) Other cases: Consult us Revision: 06-Mar-18 Document Number: 50052 1 For technical questions, contact: sferfixedresistors vishay.com THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc 91000LPS 300 www.vishay.com Vishay Sfernice PERFORMANCE TESTS CONDITIONS REQUIREMENTS IEC 60115-1 Momentary Overload 4 x P /10 s (0.25 % + 0.05 ) r U U = 5000 V max. L IEC 60115-1/IEC 30068-2-14 Test Na Rapid Temperature Change 50 cycles (0.5 % + 0.05 ) -55 C to +120 C IEC 60115-1 Load Life (0.5 % + 0.05 ) 1000 h (90/30) P at 85 C r IEC 60115-1 Humidity (Steady State) (0.5 % + 0.05 ) 56 days RH 95 %/40 C MIL STD 202 method 204 cond. D Vibration (0.25 % + 0.05 ) (10 g 5/500 Hz) IEC 60115-1 Climatic Sequence (1 % + 0.05 ) (55 / 120 / 56) RECOMMENDATIONS FOR MOUNTING ONTO A HEATSINK Surfaces in contact must be carefully cleaned. The heatsink must have an acceptable flatness: From 0.05 mm to 0.1 mm/100 mm. Roughness of the heatsink must be around 6.3 m. In order to improve thermal conductivity, surfaces in contact (alumina, heatsink) should be coated with a silicone grease (type Bluesil Past 340 from BlueStar Silicones) or a thermal film (type Q Pad II) easier and faster to install than the grease. The fastening of the resistor to the heatsink is under pressure control of two screws tightened at 2 Nm for full power availability. LPS 300 Tightening Torque on Heatsink 2 Nm The following accessories are supplied with each product: - 2 screws CHC M4 x 25 class 8.8 and 2 M4 contact lock washers for heatsink mounting - 2 screws TH M4 x 6/6 and 2 M4 contact lock washers for connections. 2 off CHC M4 x 16/16 class 8. CHOICE OF THE HEATSINK The user must choose the heatsink according to the working conditions of the component (power, room temperature). Maximum working temperature must not exceed 120 C. The dissipated power is simply calculated by the following ratio: T P = ------------------------------------------------------------------------------------------- R ++R R TH (j - c) TH (c - h) TH (h - a) P: Expressed in W T: Difference between maximum working temperature and room temperature R : Thermal resistance value measured between resistive layer and outer side of the resistor. TH (j - c) It is the thermal resistance of the component: (see specifications environmental paragraph). R : Thermal resistance value measured between outer side of the resistor and upper side of the heatsink. TH (c - h) This is the thermal resistance of the interface (grease, thermal pad), and the quality of the fastening device. R : Thermal resistance of the heatsink. TH (h - a) Example: R for LPS 300 power dissipation 180 W at + 50 C room temperature. TH (c - a) T 120 C - 50 C = 70 C T 70 R + R + R = ------- = -------- = 0.388 C/W TH (j - c) TH (c - h) TH (h - a) P 180 R = 0.112 C/W TH (j - c) R + R = 0.388 C/W - 0.112 C/W = 0.276 C/W TH (c - h) TH (h - a) Revision: 06-Mar-18 Document Number: 50052 2 For technical questions, contact: sferfixedresistors vishay.com THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc 91000