Hello Mak,

I think there may be some confusion about the input range--unless I misread it, it is from -0.3VDC to VCC+0.3VDC. We use the chip with an input range from 0 to 2.5VDC with overall good results. I havn't used the internal temperature sensor, so I'm unsure about that. Is the problem that you are seeing your digital reading vary when your analog inputs are shorted togethor? It sounded like you have less noise with the eval board. The digital noise can be lessened in some cases by the acquisition time you specify when you set up the analog capture. You will always have the ADC hunting to some degree so that the LSB is shifting around. Our experience is that with that chip we see +/-2 LSBs of noise on average. Depending on the board and the channel, we see as much as 3LSBs of digital noise, and as low as 1. I hope this helps.

Best Regards,

Josh