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ADS1298: Power Supply requirement for ADS1298

Anur@g Tamboli
Intellectual 620 points
Part Number: ADS1298

Dear Sir/Ma'am,

I am trying to interface ADS1298 with MCU. I have ADS1298 Evaluation kit which comes with Modular Motherboard from TI. 

I am little bit confused about power supply requirement of ADS1298, does it require all power supply variations like 1.8V, 3.3V, and 5V to work properly?

I was going through power supply requirement of ADS1298. In user guide i found below text. 

"The ADS1298 can operate in a single supply with +3.0V to +5.0V analog supply (AVDD/AVSS) or bipolar

mode supply (±1.5V to ±2.5V). An additional digital supply of and +1.8V to +3.0V digital supply (DVDD) is

required for operation."

ADS1298 is powered by J5 connector in MMB (schematic mentioned below).

and J5 connected to J4 Connector on ADS1298 Evaluation Kit (Schematic Mentioned Below).

So till my understanding, it uses +5VD, +3.3VD, +1.8VD, AGND pins only. No additional digital supply(because i can see DGND pin is not used).

I am novice with this stuff, I just wanted to clarify if i give 3.3V supply from TI MCU, will it work properly?

Regards

Anurag Tamboli

  • 0
    TI__Mastermind 47595 points
    Hello Anurag,

    Thank you for your post and interest in the ADS1298!

    Deciding what voltages to run your power supplies at is dependent on what type of inputs you'll be measuring with the device.

    Are you measuring single ended or differential signals?
    Are the signals positive with respect to ground or will they be negative?
    What full scale range and gain settings would you like to use? (Section 9.3.1.5)

    Using the 3.3V supply from the TI MCU for AVDD is acceptable, but you will need 1.65V to 3.6V for DVDD as well.
  • 0 in reply to Alexander Smith
    Intellectual 620 points
    Hi Alex,

    Thanks for replying. Lets just assume i am measuring physiological signals like ECG or EMG from the human body. Those signals can be differential or signal ended signal. Still will i be needing 1.65V to 3.6V for DVDD as well. But in schematic suggests otherwise.
    I wanted to acquire signal at 1000 SPS and PGA value can vary from 6 - 12.

    Regards
    Anurag Tamboli
  • 0 in reply to Anur@g Tamboli
    TI__Mastermind 47595 points
    Hello Anurag,

    Happy to help!
    Yes, you will need a voltage to power the digital side of the board. The ADS1298 is capable of powering the digital pins with a voltage from 1.65V-3.6V, but the MMB0 board only offers 1.8V & 3V options. Both the 1.8V and 3V are acceptable to use.

    The device does not need all combinations in order to work properly. Using the jumpers will select which traces are connected to the device and therefor which voltages the device is using.

    You will need to connect AVDD & AVSS.
    For single ended, AVDD = +3.0V or +5.0V, and AVSS = AGND
    For Differential, AVDD = +1.5V to +2.5V, and AVSS = -1.5V to -2.5V

    You will need to connect DVDD.
    The MMB0 offers a 1.8V or a 3V connection for DVDD. Using either of these is acceptable.
  • 0 in reply to Alexander Smith
    Intellectual 620 points
    Hello Alex,

    Sorry for late reply. Thank you for the reply. It really helped alot.

    Regards
    Anurag Tamboli