AD9283-100 reference voltage

Hi! 

I am using AD9283-100 operating at 50MHz. Ian using internal reference. I am always getting output code as all zeros. When I monitored the Vref at Pin 2 and Pin 3 shorted to ground I am getting 1.82V instead of specified 1.25V. what could be the reason.

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  • 0
    •  Analog Employees 
    on May 8, 2017 10:01 PM

    Hi Satish,

    Internal Reference mode is enabled by strapping VREF OUT (pin 2) to VREF IN (pin 3) as described in the Voltage Reference section on datasheet pg 8, and shown in the eval brd schematic fig 13. The VREF OUT (pin 2) also needs to be bypassed with a 0.1uF capacitor to Ground.

    Please clarify your comment "When I monitored the Vref at Pin 2 and Pin 3 shorted to ground I am getting 1.82V instead of specified 1.25V" VREF pin2, or pin3 should never be shorted to Ground. Please post your AD9283 schematic and/or insure it conforms to the example circuit shown in datasheet fig 13.

    Best Regards,

    TonyM

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  • 0
    •  Analog Employees 
    on May 8, 2017 10:01 PM

    Hi Satish,

    Internal Reference mode is enabled by strapping VREF OUT (pin 2) to VREF IN (pin 3) as described in the Voltage Reference section on datasheet pg 8, and shown in the eval brd schematic fig 13. The VREF OUT (pin 2) also needs to be bypassed with a 0.1uF capacitor to Ground.

    Please clarify your comment "When I monitored the Vref at Pin 2 and Pin 3 shorted to ground I am getting 1.82V instead of specified 1.25V" VREF pin2, or pin3 should never be shorted to Ground. Please post your AD9283 schematic and/or insure it conforms to the example circuit shown in datasheet fig 13.

    Best Regards,

    TonyM

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