SanDisk Product Development Engineer II interview questions

It was a 6+ weeks process. I forwarded my resume to a team member. It was followed by a phone screen round and one hour phone interview with the manager. I was called on-site the following week which had 4 rounds containing 45 minutes each. Since the position demands to have knowledge about NAND Flash memories, most of the questions were on working of pn juctions, MOSFETS, RC circuits, NAND Flash basics. After 3 long weeks of waiting period, I was informed that I was rejected.