AD5322 offset error

Helo.

I use DACs AD5322. In channel A offset error voltage 21mV, if i write code 0x000 to DAC register. In channel B offset voltage 4.5mV. And it offset save for all power band, until Vref. In this case voltage output = Vref+offset error voltage.

This offset voltage value within the limits normal?

Vdd=5V, Vref=4.5V.

http://www.analog.com/static/imported-files/data_sheets/AD5302_5312_5322.pdf_

Thanks.

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  • 0
    •  Analog Employees 
    on Dec 12, 2012 1:31 PM

    Hello,

    There is a lower deadband on this DAC that tells you that it is 60mV so sometimes it might not scale if you take 0x0000 to be your offset. If you are calibrating it might be wiser to take your measurment above code 115.  If you take a look at the figures on page 6 there is a graphical descrition but this is due to the output amplifier.

    That said the offset spec is typically +/-0.4 % of FSR which, with a 4.5V reference voltage is +/-18mV typically and the max spec is much greater so you are getting values close to this. These are expected values.

    Regards,

    Padraic

    Aplications Engineer

    Precision Converters

Reply
  • 0
    •  Analog Employees 
    on Dec 12, 2012 1:31 PM

    Hello,

    There is a lower deadband on this DAC that tells you that it is 60mV so sometimes it might not scale if you take 0x0000 to be your offset. If you are calibrating it might be wiser to take your measurment above code 115.  If you take a look at the figures on page 6 there is a graphical descrition but this is due to the output amplifier.

    That said the offset spec is typically +/-0.4 % of FSR which, with a 4.5V reference voltage is +/-18mV typically and the max spec is much greater so you are getting values close to this. These are expected values.

    Regards,

    Padraic

    Aplications Engineer

    Precision Converters

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