This slide shows an example of an SOA graph from a MOSFET datasheet. The x-axis is MOSFET drain-to-source voltage and the y-axis is MOSFET drain current. Both axes use a logarithmic scale. On this graph, the straight-line curves depict constant MOSFET power. The curves show power dissipation allowed in the MOSFET for a specific pulse period with the pulse period ranging from ms to infinity, or DC. For example, the circled data point shows that for a 10ms pulse period the MOSFET can have 30A flowing through it with 10V across drain to source, which calculates to 300W of power dissipation. Lower power for the same time period ensures safe MOSFET operation which can be denoted as an area of the graph under the curve, leading to the term: safe operating area.