I've been using the ADS8321 a lot lately in prototypes I'm working on for use with strain gauges. I'm using an Analog Devices AD623 to amplify the signal and then into the ADS8321. It's been working perfectly with several setups on proto-boards and a couple of PCB's I design. However recently two started reading out in a peculiar way.
Say it's reading out -5096. If I apply load to the strain gauge instrumented lever, it'll jump to -5104 then -5108, 5110,5111 then 5623, 5879. So it's cycling changing only each bit (8, 4, 2, 1, 512, 256 onwards )and inbetween not changing the lower bits until it reaches 0 and then jumps to 512.
However the loads related to these values are generally correct. It's like variable length dead zones.
What's strange is that there are two on the current board and both started acting up at the same time.
Has anyone experienced TI ADC's with such a werid output? should I jump to replacing the IC's? Is something bridged? I haven't done any work on the board in a few weeks?