• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 2 answers
  • Subscribers 46 subscribers
  • Views 2018 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

ADS1298: Need a reference circuit for EMG

Sandeep Reddy1
Prodigy 30 points
Part Number: ADS1298

Hi Everyone, 

I recently ordered a ADS1298 DK for EMG application. I am confused on how to connect the 3 pin emg to the ADS pins?

I am connecting EMG's Mid and End muscle to the OpAmp's inputs (1 channel) and the 3rd reference pin to ADSS pin as an analog reference to the circuit.

Can you let me know if this configuration is Okay or I need to change the configuration. And also, if I add more channels, do I need to add any other reference pins?

Thank you for the help.

  • 0
    TI__Guru 55342 points
    Hi Sandeep,

    Thanks for your post and welcome to the forum!

    Unfortunately I am not aware of an EMG reference circuit, nor am I an expert on the EMG application - so the support I can offer is limited to the device.

    When you say ADSS, do you mean AVSS? If so, I do not believe that is correct since AVSS is the negative power rail.
  • 0 in reply to Alexander Smith
    Prodigy 30 points

    Hi Alexander,

    Thanks for the reply. I have attached the reference circuit here for EMG.

    As far as I understand from EMG, the reference of the EMG electrode is connected to the ground so that there is no external interference.

    So, going by the EMG basics, I was thinking of connecting the reference to AVSS and not ADSS (Sorry). Can you suggest any changes?

    Thanks and Regards,

    Sandeep.

  • 0 in reply to Sandeep Reddy1
    TI__Guru 55342 points
    Hi Sandeep,

    I see, thank you for the graphic.

    I would recommend setting the reference voltage at mid supply. So if you're using unipolar supplies (AVDD = 5V, AVSS = 0V/GND), that means setting the reference to 2.5V. For bipolar supplies (AVDD = 2.5V, AVSS = -2.5V), that means setting the reference to GND. This will ensure that the resulting signal is within the common-mode range of the PGA. Neither case will work with connecting this to AVSS, I recommend using the RLD function of the device to set the reference.

    This thread may help: e2e.ti.com/.../300254