AD9283 Reference Voltage

Please advise.
I use AD9283.
There is an item of "Reference Voltage" in "ANALOG INPUT" of a datasheet.(REV. C P2 )
Does this Reference Voltage mean input of a REFIN terminal?
Or is this description about output of a REFOUT terminal?

If I'm inputting the voltage outside the area to a REFIN terminal, is that guaranteed?

If I input the voltage of the 0.7V to a REFIN terminal, is that permitted?

 

Regards,

  • 0
    •  Analog Employees 
    on Oct 27, 2016 7:29 PM

    Hi,

    A stable and accurate 1.25 V voltage reference is built into the AD9283 (VREF OUT, pin 2) as described on datasheet pg 8. The specification table you reference below describes the accuracy of the fixed internal VREF voltage output at pin 2. In normal operation, the internal voltage reference is used by strapping Pins 2(VREF OUT) and 3(VREF IN) of the AD9283 together. The ADC input range can be adjusted slightly by not using the fixed internal reference, but instead by applying an external reference voltage to the VREF IN, pin 3 of the AD9283. The allowable operating range when using the external reference is similar to the internal reference. No degradation in performance occurs when the external reference is adjusted to ~1.25V±5%. The full-scale range of the ADC tracks reference voltage changes linearly. Whether used or not, the internal reference (Pin 2) should be bypassed with a 0.1 µF capacitor to ground.

    No, the AD9283 does not support an external VREF IN of 0.7V without degradation in performance.

    Best Regards,

    TonyM