AMC1301: TIDA-01513: how to handle the connection between GNDi and HV_NEG

Hi Zhonghui,

Thank you for posting this question. This is an older design and I agree that the GNDi net must be referred to the negative input in some way to ensure no input common-mode violation. I'll contact the SEM team in regards to having this changed. 

I would recommend a split-tap connection where R7 (1k) is split into two equal value resistors (500) and the high side ground (GNDi) is connected between them. I've explained this solution in this thread: https://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/1099833/amc1300-tina-spice-simulation-with-common-mode-voltage-step/4077234#4077234

Furthermore, I would not recommend the AMC1301 for this measurement. The AMC1301 is an older device and we have newer pin to pin devices available such as AMC1300. A device with higher input impedance (AMC3330, AMC1350) would be desired to reduce the potential error due to input resistance variation. 

Please review and let me know if you have any questions. 

Kai,

Thank you for the help but there may be some confusion. What you said for the output is valid but the schematic is reversed and the question is about the input, not output.

Hi team,

Thank you for your help.

I have informed your reply to the customer.

Best regards,