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ADS1299: Circuit schematics and design for ADS1299

mubeen khalid
Prodigy 155 points
Part Number: ADS1299

I have bought a new ADS1299 For my 8 channel EEG board as my final year project in University. I want to acquire my 8 channels data on. The first step was to solder it on a breakout board which was a hectic task, but fortunately it went well. 

Now the main problem is the components like filters and capacitors required to drive my circuit. I searched all forums but no correct circuit was there. Can anybody provide full circuit schematics for ads1299 it will help alot. I want a 8 channel EEG so following are my questions.

  1. I want to use a Unipolar supply of 5 volts analog and 3.3 volts digital. So will it distort the negative components of my signal? Or i have to use bipolar supply to accompany negative part of my signal.
  2. What should be the filter values at inputs both positive and negative. What components should be there.
  3. Does ads1299 have Right leg drive circuit . If yes than how can i use it and can connect electrodes to it.
  4. At reference terminals how can i select the capacitors .

At the end again it will be a great help if any one provide exact circuit schematic for ads1299.

  • 0
    TI__Guru**** 180961 points
    Hi mubeen,

    Welcome to our e2e forum! The easiest place for you to start would be to take a look at the schematic in the back of the ADS1299EEGFE-PDK users manual. There are filter options there as well as ideas for using a bi-polar and uni-polar supplies.
  • 0
    Intellectual 690 points
    Hi,
    a brief comment to the questions above:
    1) using unipolar supply won't destroy your signal. It is all about mid-supply value: when you have an unipolar supply the amplified signal will fluctuate around the mid-supply value.
    2) filter values should be the identical; as far as I remember the filter group recommended in the ADS1299 kit was R=4.99k C= 4.7 nF; you can also consider to connect the capacitor directly between the relevant inputs (+/- or in case of using SRB1: + - SRB1) instead of having a separate capacitor between each input and GND.
    3) ADS12999 does have a circuit with a similar purpose. The relevant output is called "BIAS" in this case and most often connected at the region of right or left mastoid.
    4) for practical purpose you can simply follow the values recommended in the ADS1299EEGFE-PDK ADS1299 Performance Demonstration. It would be very useful for you to study that document in details.