I have brought some MAX3421e from an online store. But I found them didn't work. Finally, I found the oscillator(12Mhz) didn't work.
And after I replaced with MAX3421e chips from another online store, it works.
In the datasheet of MAX3421e , the EP should be like below:
But the one which can't work is as below (it's square):
And the EP of the one which works well is as below
My question is：have you even produce a MAX3421e with square EP? Does it means I have brought fake IC？