External Heatsink and PCB Leads Alignment Guidelines (Continued)

TO-220 Power Resistor

Package Mounting Guide (Continued)

It is important that the packages are correctly mounted if full functionality is to be achieved. Mounting of the

package to a heat sink must be done such that there is sufficient pressure from the mounting screws to

insure good contact with the heat sink for efficient heat flow. Incorrect mounting may lead to both thermal

and mechanical problems. Over tightening the mounting screws will cause the package to warp reducing

the contact area with the heat sink and increasing the thermal resistance from the package case to the heat

sink, resulting in higher operating die temperatures. Extreme over tightening of the mounting screws

beyond the recommended torque force will cause severe physical stress resulting in cracked die and

catastrophic IC failure. Though the reliability of the package is excellent, the use of inappropriate

techniques or unsuitable the long tools during the mounting process can affect term reliability of the

device and even damage it.

Figure (1)

Figure (2)

Figure (3)

Figure (4)

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