AD7856 Calibration mode and test mode

Hi ,

     My customer is using AD7856 now, They don't know when they should use Calibration mode and test mode, And there are no more detailed description  about test register and calibration register,Would you please offer more document to descript how to use these register? Thanks very much!

     Avnet Echo

  • 0
    •  Analog Employees 
    on Jan 11, 2015 5:58 PM

    Hi,

    As stated in the AD7856 datasheet, the Test Register is used for testing the part and should not be written to.

    The part can be configured to do automatic calibration on powerup through the /CAL pin. Through the control register, a self- and system calibration can be done. Details on calibration types can be seen on Table IV of the datasheet. There is a section for Calibration Registers on the datasheet, does the customer have anything specific in mind that has not been covered in this section?


    Regards,

    Karen

  • Hi Karen,

         Thanks for your kindly reply, You means the test register just for factory test without customer's intervention?

    For Calibration registers, The system could detect  offset error and gain error and calibrate these parameters automatically?

         Thanks.

         

         Echo

  • 0
    •  Analog Employees 
    on Jan 25, 2015 5:48 PM

    Hi, Echo.

    Apologies for the delayed response. Yes, you are correct about both.  The default setting is a full internal calibration where the Internal DAC is calibrated followed by the Internal Gain Error, and finally the Internal Offset Error is calibrated out. This and other calibraiton types are outlined in Table IV on page 11 of the AD7856 datasheet.

    Regards,

    Karen