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ADS131E08: Power dissipation

Sunney Kumar
Prodigy 60 points
Part Number: ADS131E08

Hi, I am using ADS131E08IPAGR in one of the designs and need information on power budgetary for this part.

Please refer below specs for application.

  • AVDD = 5V
  • DVDD = 3.3V
  • All the analog input pins are used.
  • Internal op amp is not used (pins 61, 60 & 63)
  • All digital pins are engaged.

As per datasheet, in Electrical Characteristics

I_AVDD = 5.8mA (Typ)

I_DVDD = 1mA (Typ)

In Absolute Ratings section:

Input current (Momentary/ Continuous) = 100/10mA respectively

Can you help calculating the power dissipation.

Regards,

Sunney

  • 0
    TI__Mastermind 39285 points

    Hi Sunney,

    The power dissipation is already shown on page 11 of the ADS131E08 datasheet, see the specification below:

    Regards,

    Dale

  • 0 in reply to Dale Li
    Prodigy 60 points

    Hi Dale,

    Thank you for your response.

    Yes, it is shown but along with that there is a text saying that it is Quiescent power dissipation. Can you clarify why Normal mode is under Quiescent Power dissipation.

    And why the Input current (Momentary/ Continuous) = 100/10mA respectively as shown in datasheet "Absolute Ratings" section. In what scenario we can expect this?

    Regards,

    Sunney

  • +1 in reply to Sunney Kumar
    TI__Mastermind 39285 points

    Hi Sunney,

    I understood the confusion to you. The power dissipation specification of normal mode in this parameter table 7.5 was characterized under the following certain conditions and the internal operational amplifier was turned off, however the ADC was running in a fully functional operation.

    • Test conditions:  TA = 25°C, AVDD = 3 V, AVSS = 0 V, DVDD = 1.8 V, internal VREFP = 2.4 V, VREFN = AVSS, external clock = 2.048 MHz, data rate = 8 kSPS, and gain = 1.

    You can also find the graph of power dissipation in the figure 14 of the datasheet below, the power dissipation value in this graph (all channels are enabled) matches the power dissipation specification of normal mode in the parameter table 7.5 too.

    The Absolute Maximum Ratings (AMR) table 7.1 of the ADS131E08 datasheet specifies the maximum conditions including input current (Momentary/ Continuous = 100/10mA) that can keep the ADC safe, you can see the note under the table:

    • Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

    The parameters in this AMR table are not related to power dissipation. The ADC is safe as long as the AVDD and DVDD are stayed within the ranges in the AMR table.

    Regards,

    Dale