Now I consider to use AD7606.
AD7606 has 8 channels for input, but I don't use all of the channels.
In the datasheet, for the Vx and VxGND pin which is not be used, it is recommended to connect their pins to the ground.
But I want to leave their pins open because I will use add input channels in future.
Is it OK to leave the Vx and VxGND pin which is not used open?