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Dear all:
I am working in a project using de SAR_ADC_Seq component on PSOC5. I need to measure several currents. I am using INA138 from TI which give a output current proportional to the current to be measured. Adding a resitor to the output of the INA138 converts the ouput to voltage so I can measure them with the SAR_ADC. I have 8 channels in the ADC to measure 8 different currents. INA138 recommends to buffering the output signals (see attached image) before the ADC. My question: should I use a these buffers before the SAR_ADC_Seq?
The RL of the image in my system is 91K.
I dont see any data on the datasheet about the input impedance of the SAR_ADC_Seq and not any topic similar to this on Cypress comunities/forum.
If you need further details please do not hesitate to ask me.
Thanks in advance,
Joaquin.
Solved! Go to Solution.
- Labels:
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PSoC 5 Architecture
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PSoC 5LP
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Yes, you will need a buffer amplifier. To reduce device count etc I would suggest the following:
- Separate the the analog mux and the ADC and build your own SeqADC
- Use a PSoC5 internal buffer amp or a follower past the AMUX
- Connect AMP output to ADC
This way you just need one internal OpAMP, no more external parts needed.
Bob
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Yes, you will need a buffer amplifier. To reduce device count etc I would suggest the following:
- Separate the the analog mux and the ADC and build your own SeqADC
- Use a PSoC5 internal buffer amp or a follower past the AMUX
- Connect AMP output to ADC
This way you just need one internal OpAMP, no more external parts needed.
Bob
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Thank you Bob, as usefull as always. Great idea.
I will do so.
Regards,
Joaquin.