I am using MAX 232 for 3.3 volts operation. Since the chips meant for 3.3 volts are not cost effective, I have been using MAX 232 itself. When input levels are 3 to 3.2 volts, I used MAX 232 with both 3.3 volts supply and 5 volts supply. In bot the cases, MAX 232 works correctly, providing sufficient voltages for the other side. It works with other MAXs, and PCs. Cable length used was 2 meters.

What is a better supply for 3.3 volts operation? Is it 3.3 or 5 ?

Kindly guide...