Hi Charles,
Thank you again!
Q3: So LM96550 CANNOT support CW up to +/-50V. Since the bottleneck is with LM96550, why LM96530 was damaged? I'm sorry that I do NOT really understand what you have said in previous post --- "The reason the LM96530 is shorted is because VSUB (VSUB of LM96530 is connected to VSUB of LM96550) is higher than the LM96530 VSS pin. This condition causes latchup."
Q5: I just check my PCB layout. The traces on LM96550 output is from minimum 2306 mil to maximum 7538 mil. What the maximun traces is recommanded by TI ?