What's the difference between AD8138AR-EBZ and AD8138AAR-EBZ?
The only difference between the two evaluation boards is the ADI part used wherein AD8138AR-EBZ utilizes AD8138 while AD8138AAR-EBZ utilizes AD8138A. The latter, AD8138A, is neither mentioned on the AD8138 product page nor on the AD8138 datasheet however, the table below shows the main differences between the two products and also the attached AD8138A datasheet may also be of help to you.
-3dB Small signal bandwidth (typ)
Input offset voltage for VOCM to ±OUT (typ)
Quiescent current (typ)
I hope this helps you.