Dear Chris,tThanks very much for your apply.
The differential input is 5V for the amplitude and just as you said, the input was achieved by applying +2.5V to AINP and -2.5V to AINN. Also, the input is 1Hz sine wave. But the amplitude limiting was happend when the input is +1.5V and -1.5V.
Best Regards
Li Hao