40 - 48 WEEKS?? How the HELL can you run a business with that kind of lead time? I did, once, have a part with an insane lead time. It was a 4-channel DAC, I was paying $30 each for them, and the distributor said they were on back order with no clear delivery time. I inquired direct to the manufacturer, and they eventually sent me an email with the exact date the parts would be produced -- over TWO YEARS in the future!
I was in a panic, and started searching what little info was on the web back in the late 1990's. I found TI had a part with a similar number, and reading the data sheet, it appeared to be a drop-in replacement, at only, $3 each. I ordered some, all the while thinking "there's got to be a catch, I can't replace a $30 part with a $3 part, can I?" Well, the $3 in-stock part worked perfectly.
I've had a few other parts that got hard to get, but I've been able to find them SOMEWHERE.
But, then, I had some single-source parts that were PERFECT for the application, and then they were discontinued! I had to redesign the board. UGH!
Jon