Part Number: ADS7828
Hi,
I'm Bob Mao from Iris power, A Qualitrol Company. Recently I joined our NPI team to finish my new product release and found ADS7828 was used for voltage rails monitoring. The design used single end 8 to 1 to monitor voltage but I found the pin COM is floating. I checked the datasheet, this COM pin should be connected to GND when work in single end input mode. For last 2 spin boards, they didn't found any reading issue even thoung this pin is floating, but for the lastest spin board, I found some boards have reading issue. ADC result is not accurate. But when I short pin COM to GND, then every reading is normal without any issue. We didn't change design and layout for all 3 spin boards. And also know we can solve this reading issue by adding a short wire between pin COM and GND. My question is: Why first 2 spin boards had no reading issue with pin COM floating? Is there any connection inside the chip or is there any command sent by I2C can connect this pin COM to GND? Thanks for your help, I'm really appreciate it.
Regards,
Bob Mao
Senior Hardware Designer
Development Department
Iris Power LP, A Qualitrol Company