That would be High Reliability Part Numbering System .
"CD4040B-MIL" is what the website calls the device, but the orderable part numbers are CD4040BF and CD4040BF3A.
("CD4040B" is what the website calls the non-military device; its orderable part…
Part Number: CD4013B-MIL Other Parts Discussed in Thread: SN54LVC74A-SP , CD4040B-MIL , CD4047B-MIL , CD4070B-MIL , CD4081B-MIL , SN54LS393-SP , SN54LVCH244A-SP , SN54LS08-SP Tool/software: We are looking for Radiation Tolerance value for the above part…