ADuC702x max. input voltage for Analog Inputs & Vref

Can the ADuC702x be used with 3.3V on the analog inputs?

Internal Vref is only 2.5V

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  • 0
    •  Analog Employees 
    on Aug 4, 2010 4:16 AM

    The max. input voltage for the analog inputs is specified in the datasheet

    with absolute max ratings = AVDD + 0.3V (page 16 of the datasheet)

    http://www.analog.com/static/imported-files/data_sheets/ADuC7019_7020_7021_7022_7024_7025_7026_7027_7028_7029.pdf

    So if the part is operating as on the evaluation-board at 3.3V,

    a 3.3V input to the analog channels is no problem - the part can't be damaged.

    But you have to take in account that the internal Vref is only 2.5V, so every

    measurement between 2.5V and 3.3V returns the max. ADCDAT value of 0xFFF = full-scale.

    But you can use a external 3.3V reference to measure correctly as well the 3.3V input voltage.

    In the absolute max. ratings the max. AVDD < =  6V!

    But the specification for the part is only valid for the

    operating voltage range from 2.7V to 3.6V (datasheet page 6)!

Reply
  • 0
    •  Analog Employees 
    on Aug 4, 2010 4:16 AM

    The max. input voltage for the analog inputs is specified in the datasheet

    with absolute max ratings = AVDD + 0.3V (page 16 of the datasheet)

    http://www.analog.com/static/imported-files/data_sheets/ADuC7019_7020_7021_7022_7024_7025_7026_7027_7028_7029.pdf

    So if the part is operating as on the evaluation-board at 3.3V,

    a 3.3V input to the analog channels is no problem - the part can't be damaged.

    But you have to take in account that the internal Vref is only 2.5V, so every

    measurement between 2.5V and 3.3V returns the max. ADCDAT value of 0xFFF = full-scale.

    But you can use a external 3.3V reference to measure correctly as well the 3.3V input voltage.

    In the absolute max. ratings the max. AVDD < =  6V!

    But the specification for the part is only valid for the

    operating voltage range from 2.7V to 3.6V (datasheet page 6)!

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