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.

ADS1298ECGFE Power-related Query

Other Parts Discussed in Thread: ADS1298ECGFE-PDK, ADS1298

Hi,

I recently purchased the ADS1298ECGFE-PDK (Analog front end + MMB0). 

I'm currently exploring the use of the ASD1298ECGFE with another microcontroller. Thus, I'm trying to understand how the ADS1298ECGFE is meant to be powered up. I'm reading the datasheet but i don't understand what is required. 

 The ADS1x98EVM mounts on the MMB0 EVM with connectors J2, J3 and J4. The main power supplies

(+5V, +3V and +1.8V) for the front-end board are supplied by the host board, MMB0, through connector

J4. All other power supplies needed for the front-end board are generated on board by power

management devices. The EVM is shipped in +3V unipolar supply configuration.

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. The ADS1298EVM power consumption can be measured by removing the JP4

jumper and JP24 jumper to connect an ammeter. By shorting JP5, the ADS1298 can be placed in

powerdown mode for low power consumption.

 The front-end board must be properly configured in order to achieve the various power-supply schemes.

The default power-supply setting for the ADS1298ECG-FE is a bipolar analog supply of ±2.5V and DVDD

of either +3V or +1.8V. Table 7  shows the board and component configurations for each analog powersupply

scheme and Table 8  shows the board configurations for the digital supply.

In the first paragraph, it says that I need to supply 5V, 3V and 1.8V at the correct pin to J4 connector and the on-board power management will provide the necessary powers. 

However, in the last paragraph, it says that I need to provide bipolar and digital supply. 

  • Bipolar analog supply of +/- 2.5V
  • Digital supply of either 3V or 1V

Could you please advise. 

Thanks

Regards,
Aslam

  • Hi Aslam,

    Thanks for your question!

    The 5V, 3V, and 1.8V supplies are provided from the MMB0 through the J4 header on the bottom of the ADS1298ECGFE-PDK daughterboard. If you are using the daughterboard without MMB0, you can connect your own power supplies to TP7 (5V), TP10 (3.3V), and TP9 (1.8V).

    The 5V supply (VCC_5v) is used to generate the different analog supply options (+3.0V, +2.5V, -2.5V). JP2 and JP20 are used to select the supply voltage for AVDD and AVSS, respectively (JP2 selects either +3.0V or +2.5V for AVDD; JP20 selects either 0V or -2.5V for AVSS). Please refer to page 59 of the User's Guide to see the power tree for the analog supplies. Also, make sure that the supply configuration you choose does not violate the ADS1298 supply requirements (i.e. do not choose +3.0V for AVDD and -2.5V for AVSS, it is not a supported configuration and may damage the part).

    The 3V and 1.8V supplies (VCC_3.3V and VCC_1.8V) are provided through J4 as options for the digital supply, DVDD. Use JP24 to select one or the other.

    Best Regards,

  • Hi Ryan, thanks for your response. 

    Just to be clarify, here is my understanding and implementation. 

    Step 1: Supply 5V to TP7 (Positive terminal to TP7, Gnd wire to TP8)
    Step 2:  Supply 3.3V to TP10 (Positive terminal to TP10, Gnd wire to TP8)
    Step 3: Supply 1.8V to TP9 (Positive terminal to TP9, Gnd wire to TP8)

    Step 4: Configure analog supply options

    Before configuring, could you kindly confirm if my understanding of it is correct: 

    AVDD and AVSS are analog supply and ground respectively. 

    The daughterboard is shipped with a +3V unipolar configuration (Pg. 41 of user guide). Therefore, since it is a +3V unipolar configuration, the AVDD (supply) should take 3V and and AVSS (gnd) should be 0V. 

    Referring to the schematic on Page 59 and Table 7 on Page 42 of user guide, I will need to set JP2 to 2-3 in order to get the +3V, and set JP20 to 1-2 in order to get the 0V gnd. 

    This is the default configuration of the EVM upon receiving it. 

    Should I wish to implement a bipolar configuration (AVDD is +2.5V and AVSS is -2.5V), I would have to change JP2 to 1-2 in order to get the +2.5V, and JP20 to 2-3 in order to get the -2.5V. 



    Therefore, Step 4, is essentially choosing whether I want a Unipolar or Bipolar configuration, and carefully selecting AVDD and AVSS. 

    Step 5: Selecting between DVDD 3.3V or 1.8V via JP24. These two voltages were originally supplied in steps 2 and 3. Should I choose to use 3.3V, based on the schematic of Page 60, can I omit the 1.8V supply in Step 3? I'm finding it hard to find a 1.8V DC supply. 


    Thus, with all these 5 steps, everything is good to go? 

    Thank you for your patience and assistance! 

    Regards,
    Aslam

  • Hi Aslam,

    Yes, you got it!

    For DVDD, you do not need to supply both 3.3V and 1.8V, only one is necessary. Whichever you choose, make sure that the digital supply is the same for both the ADS1298 and your processor. Otherwise, you will need a level translator in order for the two parts to communicate properly.

    Best Regards,

  • Thanks for your guidance. 

    I will be setting up power as such: 


    5V and 3.3V from the Arduino Uno, at TP7 and TP10 respectively. 

    JP2 setting: 2-3
    JP20 setting: 1-2
    JP24 setting: 2-3 (for 3.3V DVDD)

    Regarding what you said about the digital supply having to be same for ADS1298 and processor. By processor are you referring to the Arduino Uno that I am using? 

    The Arduino Uno runs on 5V. And since DVDD for the ADS1298ECGFE is 3.3V, i assume I will need to use a level translator like you mentioned?

    • Signals output from Arduino -> input into ADS1298
      5v - > translated -> 3.3V

    • Signals output from ADS1298 -> input into Arduino
      3.3v -> translated -> 5v

    Hope this is correct. 

    Thanks again Ryan

    Best regards,
    Mohd Aslam