TL16C2550: Can the TL16C2550 be used as a form, fit and function replacement for XR16L2550IL??

Kay,

We don't really guarantee interoperability between UART devices, even within TI's own portfolio. There are likely small differences between some logic like AND/OR gates or timing that can require the firmware to be modified. (My short answer your question is going to be no). 

Essentially the customer will need to validate the new device.

I'm also a bit hesitant to recommend this family as we've been EOL'ing the older process technologies for our UART devices as well. 

If you need a 2 channel UART device, we've been recommending the TL16C752D since that one is in the latest process technology and considered one of our 'newer' devices.

-Bobby

Thanks