PF2470 Series TO-247 Power Thin Film Resistors • • • • • • • TO-247 Housing Rated Power to 140 Watts Resistances from 0.02 to 51K Ohms High Stability Film Resistance Elements Resistance Tolerance to ±1% Low Inductance ( <50nH ) Isolated Back Plate SPECIFICATIONS Type Power Rating Heatsink1 Free Air2 Resistance Range3 Thermal Resistance Min Max Tolerances Temperature Coefficients PF2473 140W 5W 0.9°C/W 0.02W 51KW ±1% ( R ≥0.10W ) ±5% ±50ppm/°C ( R≥10W ) ±100ppm/°C ( 0.1W ≤ R < 10W ) ±250ppm/°C ( R < 0.1W ) PF2472 100W 3W 1.3°C/W 0.02W 51KW ±1% ( R ≥0.10W ) ±5% ±50ppm/°C ( R≥10W ) ±100ppm/°C ( 0.1W ≤ R < 10W ) ±250ppm/°C ( R < 0.1W ) Power rating based on 25°C Flange Temperature Power rating based on 25°C Ambient Temperature 3 Consult Factory for Higher or Lower Values 1 2 Specification Value Temperature Range -55°C to +155°C Dielectric Strength 2500 VAC Max. Operating Voltage 700 V or √P*R, whichever is less Insulation Resistance >1000 Meg-Ohm Environmental Performance DR Test Conditions Load Life ±1% + 0.05W 25°C, 90 min ON, 30 min OFF, 1000 hr Humidity Resistance ±1% + 0.05W 40°C, 90-95% RH, DC 0.1W, 1000 hr Temperature Cycle ±0.25% + 0.05W -55°C for 30 min, +155°C for 30 min, 1000 hr Solder Heat ±0.1% + 0.05W +350°C, 3s Vibration ±0.25% + 0.05W Riedon Inc. 07/13 300 Cypress Avenue IEC60068-2-6 Alhambra CA 91801 www.riedon.com (626) 284-9901 (626) 284-1704 PF2470 Series TO-247 Power Thin Film Resistors SPECIFICATIONS (continued) Power Rating Notes - Power Derating Curve 120 The PF2470 Series Thin Film Resistors must be attached to a suitable heatsink. The maximum internal resistor temperature is 155°C (120°C for the PF2201). Power ( % ) 100 80 To specify an appropriate heatsink use the following formula : 60 RqH = TMAX - ( P x RqR ) - TA P 40 20 0 -25 0 25 50 75 100 125 Backplate Temperature (°C) 150 175 Where: RqH = Thermal Resistance of Heatsink ( °C/W ) RqR = Thermal Resistance of Resistor ( °C/W ) TMAX = Maximum Temperature of Resistor TA = Ambient Temperature of Heatsink ( °C ) P = Power Through Resistor ( W ) Mounting Notes The PF2470 Series Thin Film Resistors must be attached to a suitable heatsink. Mount resistor using thermal grease to a clean, flat surface. Use a compression washer to provide 150 to 300 pounds ( 665 to 1330N ) of mounting force. Torque mounting screw to 8 in-lbs ( 0.9 N-m ). Back plate is isolated from both pins. Ordering Information Part Description: Part Type - Resistance - Tolerance - TCR Example: PF2472 10 Ohm 1% 50ppm Riedon Inc. 07/13 300 Cypress Avenue Alhambra CA 91801 www.riedon.com (626) 284-9901 (626) 284-1704