Definition of Maximum Safe Operating Area The graph covers a 2N3637 in a TO-39 case mounted package at 25C The maximum safe operating area of a transistor is the area bounded by the curve of the maximum applied voltage and maximum current requirements of the component, which defines the power dissipation of the device. Ultimately the maximum permissible junction temperature of the transistor defines the maximum possible power dissipation; however the maximum safe operating area graph depits the maximum junction temperature as current by voltage. Note that the maximum safe operating area of a device is also effected by the duration of applied voltage, as shown in the graph using different color lines.  Note the graph is Voltage x Current x Time The Safe Operating Area [SOA] is limited to a junction temperature [Tj] of 200C for a safe design. The graph covers continuous dc operation to 1uS pulses. A number of points are located on the graph for reference Vce = 5V at 1A Vce = 50V at 0.095A Vce = 100V at 0.03A Vce = 130V at 0.02A Common data sheet statement; Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under the Electrical Characteristics is not implied. Exposure to absolute maximum rated conditions for extended periods may affect device reliability. Guidelines for Derating PNP Transistors. Linked in; Dictionary of Engineering Definitions; to return to that page. |