Solution:

The non-addressable ADAM-4521 cannot replace the functions of ADAM-4520 totally. The conversion process of the ADAM-4521 is handled by a processor and it would have delay time longer than ADAM-4520. In addition, because there is a small buffer inside the ADAM-4521, it cannot handle with continuous conversion job for a long time. If you use the non-addressable ADAM-4521 to do the conversion job like ADAM-4520. It is very easy to generate the overflow situation while continuous conversion for large amount of data. Therefore please don't use the non-addressable ADAM-4521 to replace the ADAM-4520.