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ADS1220: Input range

Shota Mago
Expert 8930 points

Part Number: ADS1220

Hi team,

My customer considers to use ADS1220 and he is asking a question about input range.

He would like to measure single-ended 0~5V analog input with usage of AVDD-AVSS=5V, VREFP0-VREN0=5V.

Before the register is written to set external reference mode, there is possibility that up to 5V will be applied to input(AIN0) while AIN1 is shorted to GND.

It exceeds default internal reference voltage(2.048V).

Even though input range exceeds default internal reference voltage, it doesn't damage the device as long as input voltage is below AVDD.

Is this understanding correct?

Best regards,

Shota Mago

  • +1
    TI__Guru** 113765 points

    Hi Mago-san,

    Your understanding is correct.  There will not be any damage to the ADS1220 as long as the input voltage does not exceed the analog supply.  When the input voltage exceeds the reference voltage value, the output will read as full-scale.  

    When making single-ended measurements using a unipolar supply (AVSS= AGND), the PGA must be disabled and bypassed.  Also, you will only be able to measure the positive voltage range for the ADC,

    Best regards,

    Bob B

  • 0 in reply to Bob Benjamin
    TI__Expert 8930 points

    Hi Bob-san,

    Thanks for your quick response and clarification!

    I appreciate your kind support as always.

    Best regards,

    Shota Mago