• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 45 subscribers
  • Views 213 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

ADS131B26-Q1: ADS131B26-Q1

Enrico Silvestri
Prodigy 10 points
Part Number: ADS131B26-Q1

Guys, I'm haveing a problem reading the datasheet of this component.

1) For example What does that mean Power supply: APWR to AGND between -0.3 and 20 V. And then it says AGND, AGNDy, DGND between -0.3 and 0.3 V. And then again RCAPy to AGND between -0.3 to 2.2 V. 

And then for the Analog Input voltage it says CPY,CNy,VPy,VNy,Vxy bewteen AGND-1.6 and AVDD +0.3, what is AVDD and AGND? 

2) Here it goes again APW to AGND between 4 and 16 V. What does that mean? And 'to' what? And why is it different from before? 

3) now here you don't even have any values 

 

I'm literally going insane traying to decode this datasheet. Somebody help 

  • 0
    TI__Mastermind 22355 points

    Happy New Year Enrico!

    Welcome to our e2e forum and thanks a lot for your interest in our ADS131B26-Q1.
    I am sorry to hear that you are having trouble understanding the datasheet specifications. The way we specify it is quite common for all our ADCs and many ADCs in the industry.

    You might first want to review the "Power Supply Recommendations" section in the datasheet to get a general idea of the different power supply options that can be used with this device because the device offers some flexibility there.
    The section hopefully also clarifies what AVDD and IOVDD are for you.
    Figure 10-1 in the datasheet might also be helpful to better understand the external supply connections.

    For a circuit design you should look at the "Recommended Operating Conditions" table. These are the nominal conditions under which the device should be operated.
    The footnote below the "Absolute Maximum Ratings" table provides details on how the maximum ratings should be understood. Those conditions are useful to determine what external protection of the device might be required.

    The device has multiple GND pins, which would all be connected to the same GND plane on the PCB. That means AGND, AGNDA, AGNDB and DGND are ideally all at GND = 0V. However some PCB designs might have some parasitic impedance between the connections, which may cause a shift in the voltage potential between the analog and digital GND domains. The device can tolerate conditions where the analog GND pins can be 300mV above or below the digital GND potential.

    You don't need to worry about the RCAPy pins, because the voltage on those pins is created by the device itself. However should you accidentally short any of those pins externally, expect that the device gets damaged if you short to any voltage >2.2V. 

    The voltage between APWR and AGND needs to be between 4V and 16V, which simply means that your APWR supply voltage should nominally be between 4V and 16V.

    Digital pin voltages which are referenced to IOVDD, need to stay between DGND = 0V and IOVDD. E.g. if IOVDD is generated by the internal IOVDD LDO, then the digital pin voltages need to stay between 0V and 3.3V. If you use an external 5V IOVDD supply, then you can use levels between 0V and 5V.

    The GPIO0A/B, GPIO1A/B pins are referenced to AVDD and need to stay between AGNDy = 0V and AVDD = 3.3V.

    Let me know if that clarifies things for you.

    Regards,
    Joachim Wuerker