12.55 A power MOSFET is specified to have IDmax = 5A, VDSmax = 50 V, and PDmax = 50 W.
(a) Sketch the SOA boundaries.
(b) If the MOSFET is used in the common-source configuration as shown in Fig. P12.55, show that the maximum current occurs when VDS = 0, the maximum VDS occurs when ID = 0, and the maximum power dissipation occurs when VDS = VDD/2.
(c) For VDD = 40 V, find the smallest resistance R for which the operating point is always within the SOA. What are the corresponding values of IDmax and PDmax?
(d) Repeat (c) for VDD = 30 V.
(e) Repeat (c) for VDD = 15 V.