1.When a bipolar transistor is screwed onto a board, do not tighten the device excessively. Particular care should be exercised when tightening a device with tap screws. Depending on the tilting of screws and an electric power screwdriver, tremendous stress could damage the mold resin of the device during the last few revolutions of the tightening process. To avoid this problem, use a screwdriver with torque control.
2.Additionally, use a heatsink with sufficient thermal resistance in consideration of the worst value during operation.
Consider forced cooling using a fan or the like as necessary.
3.Use screws of a size that matches the hole diameter.
4.For information about silicone and other insulating heat dissipation sheets, contact resin manufacturers. If necessary apply silicone thermal grease to further improve heat dissipation (i.e., reduce thermal resistance).
5.The mounting plane of a heat sink should be as flat as possible. An uneven surface could subject a device to excessive stress and damage it permanently in the worst-case scenario. The most commonly used heat sinks are made of aluminum or copper, both of which have excellent heat conduction properties.
6.Do not apply any mechanical stress to a heat sink once it is attached to a device.
Except for isolating devices, a heat sink will have the same electrical potential as the collector terminal. Therefore, isolation treatment may be necessary for the heat sink.
For heat sink design, see Bipolar Transistor Application Note: Thermal Stability and Thermal Design. For the attachment of a heat sink, see the application note Power MOSFET Thermal Design and Attachment of a Thermal Fin.