Code	Definition
A	Pin to Pin drop in replacement with exact electrical features.
A/Upgrade	Pin to Pin drop in replacement, but the crossed device has better performance in specific key parameters.
A/Downgrade	Pin to Pin drop in replacement, but the original device has better performance in specific key parameters.
B	Pin to Pin compatible with minor electrical differences and/or minor package dimension also it may have a combination of upgrade and downgrade specific features.
B/Upgrade	Pin to Pin compatible with minor electrical differences and/or minor package dimension, but the crossed device has better performance in specific key parameters.
B/Downgrade	Pin to Pin compatible with minor electrical differences and/or minor package dimension, but the original device has better performance in specific key parameters.
C	Pin to Pin compatible with major electrical differences also it may have a combination of upgrade and downgrade specific features.
C/Upgrade	Pin to Pin compatible with major electrical differences, but the crossed device has better performance in specific key parameters.
C/Downgrade	Pin to Pin compatible with major electrical differences, but the original device has better performance in specific key parameters.
D	The two devices have similar functionality with a different package and/or pinout.
F/Downgrade	The crossed device has the same functionality with a smaller number of logic cells (in FPGA | CPLD projects).
F/Upgrade	The crossed device has the same functionality with a larger number of logic cells (in FPGA | CPLD projects).
F	The crossed device has the same functionality (in FPGA | CPLD projects).
S	Supplier Recommended Alternate, does not match parametric cross criteria.