A problem of ADC : input signal range..

[SeungminLee]

Hi, there.

I gonna use ADS 8317 analog-to-digital converter and have a problem during testing it.

The problem is about input signal range that I need is 0~5V.

It's so weird that according to datasheet, input range is -Vref ~ +Vref with common voltage so I used 2.5V for reference level and common voltage, too.

however, input range was bounded between -0.3V ~ 1.5V. out of thse level, signal is saturated.

I really can not figure why this happens, perhaps it must due to my inexperimented skill.

please somebody help me to solve this problem.

the question could be simple.

: with this adc, can i measure 0~5V signal? is it wrong to set 2.5V for reference and input signal offset?

the full datasheet is bellow.
https://focus.ti.com/lit/ds/symlink/ads8317.pdf

 

[erikl]

... input range is -Vref ~ +Vref with common voltage so I used 2.5V for reference level and common voltage, too.

That's correct, but up to your schematic, you didn't set the common voltage to Vref, but to GND. You should connect -IN (pin 3) to REF = +2.5V (pin 1) !