Sanjeev,

The '3232' chips have been developed so that systems can be built that use a single supply voltage, instead of both 5V and 3.3V.

As for the noise margin: The output high voltage of an I/O pin on a Cygnal device, configured as push-pull output, will be only slightly less than the supply voltage. The minimum Vih for the MAX 232 is 2V, so the noise margin is well over 1V. Also, the output impedance of a push-pull pin is very low, which means that any noise will be greatly attenuated.

I have been designing with Cygnal devices since August 2000 and many of my designs are mixed 5V/3.3V.


Regards,
Rob.