Noisy Data

Hi spc ,

Thank you for your question.

Could you share your schematics and how did you connect the multiplexer with your sensor ? 

Regards, 

Aziz

This is the schematic. Are you noticing something?

ohya FYI...I read the sensor data through I2C on the controller

 Hi spc ,

I have few questions, 

1. Why are you connecting Inductor and Capacitor across IN0A and IN0B ?
2. What is the output with out MAX4619. Are you observing proper output without MAX4619 ?

Thank you. 

Regards, 

Aziz

Hi Aziz,

The answers:

1. L and C in the schematic is required for the sensor (FDC2214) to generate an excitation signal
2. I tried to disconnect the analog mux (MAX4619), and yass the issue was gone.

Hi spc ,

The inductor should be connected in series to signal path. Can you check that and correct your schematic.

Additionally, maybe try removing the inductor from parallel to the capacitor and see the response. And then, place the inductor in series signal path. 

Regards, 

AbdulAziz

PDF 

Hi Aziz, i tried to follow a schematic of the sensor eval-module. It was parallel to the signal path, even refers to the datasheet (single-ended mode).

Hi spc , 

Could you please provide me with the following answers and possibly results/plots,

1. Where did you check at the output ? (the sensor output or the Switch) and what is the frequency of operation ?
2. Did you try to induce current or voltage sense at the sensor and see if it operates normally and then add the switch ? Could you elaborate on how you are using the switch ?
3. What is the operating condition for the switch in your test ?   

Did you make sure you follow the schematic you showed above ? 

Thank you. 

Regards, 

Abdulaziz 

Hi SPC,

Can you please provide the schematic portion showing the MAX4619 in your design and how it relates to other devices?

Can you also confirm the output of the buffer is noisy or not? Can you share scope plots at Z1, Y1 and at the output of the MAX4619 as per your diagram?

Regards,

edo