>        As I understand it, the National Part doesn't have the internal
>diodes like the L293D and L293's.  I don't have a data sheet in front of
>me, so please correct me if I'm wrong.  Also, the L293D's are common, its
>the L293's I have had trouble finding.


You're right. The LM18293N is a replacement for the L293B, not the L293D,
and it doesn't have diodes.

-bob