This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

difference in stamped code on IC

I have two board revisions, and each one has an LM25117PMH IC.  but the chips have a different code on them as well.  I am trying to find information as to what the codes mean, if its to mark a different revision of IC or if it is factory or batch number etc.

Both chips have a symbol for National Semiconductor branding

1st IC:  44A0X4U LM25117PMH

2nd IC:  51ALCCU LM25117PMH