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TO220 and TO247 Thick Film Resistors are power resistors in a semiconductor package form (TO-220, TO-247). They are characterized by being able to be directly installed on a heat sink, achieving extremely high power density and thermal management efficiency. Resistors in the TO220 package typically have a power of 20W to 50W (with an appropriate heat sink), while those in the TO247 package can reach over 100W, far exceeding traditional resistors of the same volume. These resistors have their internal components printed with thick film resistor paste on a ceramic substrate, then connected to the metal baseplate through a thermal insulating layer (usually aluminum oxide or aluminum nitride), and finally encapsulated with epoxy resin to form the TO shape, with standard spacing for the leads (TO220: 2.54mm, TO247: 5.08mm).
Small size, high power, low thermal resistance (the thermal resistance of TO247 can be as low as 1.5℃/W), high insulation withstand voltage (usually 1500VAC or higher), no inductance (suitable for high-frequency switching circuits), wide resistance range (0.01Ω to 1MΩ), accuracy up to ±1%. Due to the use of standard semiconductor packaging, existing heat sinks and mounting accessories (such as spring clips, screws, insulating washers) can be utilized. It occupies a small area on the circuit board and is suitable for high-density power design.
Buffer absorption (RCD Snubber) for switching power supplies; Gate drive resistors for IGBT or MOSFETs (for high-power driving); Pre-charging or active discharge resistors for electric vehicle motor controllers; Braking resistors for frequency converters (connected in parallel); Power stages for electronic loads; And any situation where high power dissipation is required but space is limited.
1) Calculate the actual power consumption and ensure it does not exceed the heat dissipation capacity of the package and the heat sink combination.
2) When installing, apply conductive silicone grease between the metal baseplate and the heat sink, and apply appropriate pressure (screw torque 0.5 - 1 Nm).
3) For high-voltage applications (> 500V), pay attention to the creepage distance of the pin spacing.
4) Under pulse load conditions, refer to the "Single Pulse Energy - Time" curve in the product data sheet. Common products include Vishay's D2TO20, LTO100 series, Ohmite, TT Electronics, and domestic CT, etc.
The TO220 and TO247 Thick Film Resistors combine semiconductor packaging and thick film technology, representing a significant innovation in the field of power resistors. They are particularly suitable for the miniaturization trend of modern power electronic equipment. In addition, RST Electric also offers other types of Thick Film Resistors. Please feel free to come and inquire about or purchase them!
