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ADS7959-Q1: Input inquiry

Renan Santos Adriano
Mastermind 20240 points
Part Number: ADS7959-Q1

Hello Team,

My Custome would like to know whether ADS7959QDBTRQ1 has input clamp diodes at each channel? and what is the input impedance at each channel at power off condition?

Regards,

_Renan

  • 0
    TI__Mastermind 24970 points

    Hello, 

    Yes, the inputs have an protective diode structure, that turn on when the AIN > AVDD. During this case, the current is redirected to the AVDD, thus the supply source will need to be able to sink current. 

    During this case, the input current must also be limited to 2mA. 

    Regards

    Cynthia

  • 0 in reply to Cynthia
    TI__Mastermind 20240 points

    Hello Cynthia,

    Thank you for this response. Can you provide what is the input resistance of a channel in the power-off condition of ADS7959QDBTRQ1? 

    Regards,

    Renan

  • 0 in reply to Renan Santos Adriano
    TI__Mastermind 24970 points

    The input resistance of the analog input in this case would be equivalent to a diode when conducting.


    Regards

    Cynthia

  • 0 in reply to Cynthia
    TI__Mastermind 20240 points

    Hello Cynthia,

    What is the value of input impedance at the power-off condition at each channel? Diode resistance is not given in the datasheet. Kindly help us in getting the value (number).

    Regards,


    Renan 

  • 0 in reply to Renan Santos Adriano
    TI__Mastermind 24970 points

    This information is not available.

    I would suggest following previous advice, when the AIN > AVDD, the input current is redirected to the AVDD, thus the supply source will need to be able to sink current. During this case, the input current must also be limited to 2mA by external protection. Do not consider the device impedance for this

    Regards

    Cynthia