About ADG3241 Level shift IC

Hi there,

I have a  simple question about ADG3241, level shift IC.

http://www.analog.com/static/imported-files/data_sheets/ADG3241.pdf

I want the levelshift from 3.3V to 1.8V/2.5V.

I checked out the datasheet, but I'm not sure if 3.3V logic input /output should be connected to A pin or Bpin.

Please give me answer on that.

Thanks,

Tarzan