Hello All. I am attempting to design a very accurate, low noise DAQ circuit. I will be reading off a 50mV (400A) shunt and using an ADC and a digital isolator to read the current from a DSP. Attached is a pdf of my prelimary circuit.
Things to note
1) The current is bidirectional (+/- 50mV)
2) I am using an ADUM5401 for the digital isolation. This has a built in dc-dc convertor to produce an isolated supply. I am worried about the noise this might create so I am thinking of using an external supply with an ADUM1300 (no DC-DC).
My first question is, if my signal is isolated, does it make a difference if I use an instrumentation amplifier or not? Does it make a difference if I am using a low side or high side shunt?
Secondly, I decided to go for a Max4208 for the IA. This doesn't use a standard 3 op amp design so I can have better results near 0V signals. Does anyone have experience with these?
Please let me know if you see anything I can do to improve the noise or accuracy of my circuit.
I appreciate any help that is offered, and thank you in advance.
Thanks,
Omer
Things to note
1) The current is bidirectional (+/- 50mV)
2) I am using an ADUM5401 for the digital isolation. This has a built in dc-dc convertor to produce an isolated supply. I am worried about the noise this might create so I am thinking of using an external supply with an ADUM1300 (no DC-DC).
My first question is, if my signal is isolated, does it make a difference if I use an instrumentation amplifier or not? Does it make a difference if I am using a low side or high side shunt?
Secondly, I decided to go for a Max4208 for the IA. This doesn't use a standard 3 op amp design so I can have better results near 0V signals. Does anyone have experience with these?
Please let me know if you see anything I can do to improve the noise or accuracy of my circuit.
I appreciate any help that is offered, and thank you in advance.
Thanks,
Omer
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