Power Resistors for Mounting Onto a Heatsink Thick Film Technology

Applications

• 1 % tolerance available
• High power rating = 200 W
• Wide ohmic value range = 0.046 Ω to 1 MΩ
• Non inductive
• Easy mounting
• Low thermal radiation of the case
• Standard isotope case (SOT-227 B)
• MIL-STD-202 method 301
• The user must choose the heatsink according to the working conditions of the component (power, room temperature). Maximum working temperature must not exceed 125 °C. The dissipated power is simply calculated by the following ratio:
• P: Expressed in W
• ΔT: Difference between maximum working temperature and room temperature
• RTH (j - c): Thermal resistance value measured between resistive layer and outer side of the resistor. It is the thermal resistance of the component (see table Special Features)
• RTH (c - h): Thermal resistance value measured between outer side of the resistor and upper side of the heatsink This is the thermal resistance of the interface (grease, thermal pad), and the quality of the fastening device
• RTH (h - a): Thermal resistance of the heatsink
• RTH (c - a): For RTOP 200 power rating 130 W at ambient temperature +30 °C.
• Thermal resistance (see table 1) RTH (j - c): 0.5 °C/W
• ΔT = 125 °C - 30 °C ≤ 95 °C RTH (j - c) + RTH (c - h) + RTH (h - a) = = = 0.73 °C/W RTH (j - c) = 0.112 °C/W RTH (c - h) + RTH (h - a) = 0.73 °C/W - 0.5 °C/W ≤ 0.23 °C/W