Data sheet E 5/6.838 - 10497 2 W at 70C VISHAY RFEK-2 _ high precision power resistor bulk metal The RFK power resistor utilizes the proprietary bulk metal element which combines accuracy, thermal and load stability with high frequency capabilities. Mounted in a rugged, compact, heatsink housing, the RFK power resistor can withstand extreme climatic and mechanical conditions. @ POWER RATING 2 W at 70C @ VERY LOW TEMPERATURE COEFFICIENT: +5 ppm/C max. (-55C +155C) @ VERY HIGH STABILITY <25 ppm/year or <50 ppm/3 years (shelf life) @ NEGLIGIBLE RISE TIME 1 x 10- second. RFK 49 +1 183402 5M 44415 3 +02 oa He oO tS 4 max | 10 max 19.8 +0,2 -_-_- 27.5 max Tey | 92,1 min 4,5 max et ___ 2 holes @ 3,2 +0,1 Dimensions in mm SPECIFICATIONS MECHANICAL MECHANICAL PROTECTION... aluminium heatsink / insulated case RESISTIVE ELEMENT... nickel-chromium resistors "see" 8 TERMINAL LEADS... copper 3 UNIT WEIGHT... 8 g max. a ENVIRONMENTAL TEMPERATURE LIMITS... -55C +155C CLIMATIC CATEGORY... 55/ 155/56 ELECTRICAL RESISTANCE VALUE RANGE 25 Q to 80 kQ RESISTANCE TOLERANCE... standard + 0,05 % to +1% POWER RATING... 2 W at 70C TEMPERATURE COEFFICIENT +5 ppm/C max. (-55C +155C) +1 ppm/G typical (0C +60C) DIELECTRIC VOLTAGE... 750 V INSULATION RESISTANCE... >106 MQ LIMITING ELEMENT VOLTAGE... 300 V CRITICAL RESISTANCE... 45 kQ NOISE... non measurable RISE TIME... 1 nanosecond 6-28POWER RATING CHART Fig. 2 GENERAL APPLICATIONS High precision and stability power circuitry Circuits for analog computers Force transducers Circuits requiring negligeable rise time. MARKING SFERNICE trademark, series, style, nominal resistance (in Q) tolerance (in %), manufacturing date. ' RATED POWER IN WATT 0 a 25 50 70 100 125 155 175 AMBIENT TEMPERATURE IN DEGREES CELSIUS In order to maintain stability, the nominal power (Pn) should be reduced in relation to the tolerance : +0,05% and +0,1% Power 0,25 pn. Precision resistors ORDERING PROCEDURE SERIES STYLE OHMIC VALUE TOLERANCE oa 6-29