Hi,Jcolao,
1. I used a singal generator to make a 1kHZ square wave for [0,1.8V] for my VIO is 1.8v. the picture listed as fellow:
![IMG_20131208_165945.jpg]()
2.When it connected with the PD pin, you will find the result as fellow, it will be lower. So I think it has some problem with the ADAS3023 chip.
![IMG_20131208_170033.jpg]()
Best Regards,
lorime