Rob Klein :Take the max/min values, not the "typical"
Can anyone suggest a case where the "typical" values are of any use. I wonder what they are there for, you can not design with them.
Charles Bannister: is there any data sheets that you can reference to us that would support the things you say
Yes ANY datasheet will have max/min and going outside those limits makes the design subject to (substitution) problems.
Filip Bergh: couldn't find a difference between min and max ratings, absolute maximum ratings and timings
you missed the point, I was not referring to differences between the datasheets of the two chips, What I stated was "If you do not stay within max/min in your (original) DESIGN you are likeky/guaranteed to have (substitution) problems later".

I do not think Rustus problem is in the substitution, that, in itself, should not be a problem, I think it is in the original design going outside the max/min limits.

Erik