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AD9208 Eval Board showing ~ 7.5dB less power

Question asked by Dwijen.Pandya on Nov 12, 2017
Latest reply on Nov 13, 2017 by UmeshJ

Hi,

I am using AD9208 evaluation board to evaluate device. The evaluation board setting is given below and also be seen in the attached snapshot.

Sampling Rate: 3GSPS, Full BW mode

DDC Disabled

Decimation: 1

Number of bits N: 16

The ADC is set to the default full scale setting of 1.7v pk-pk. Ideally when I apply input signal of the power 8.5dBm at the input SMA J101, I should see the code swing close to the full scale. However I am seeing the code swing around -7.5dBFS. I am only getting the swing till full scale when power is increased to around 16dBm.

 

This observation is consistent at almost all frequencies. I have verified behavior for 100MHz, 1GHz, 2.2GHz etc

 

Is this behavior expected? Is there a way to get rid of this additional ~7.5dB loss?

 

Regards,

Dwijen Pandya

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