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AD8330 Single Ended Operation

Question asked by trecb on Jun 27, 2017
Latest reply on Jun 27, 2017 by JinoL



I'm using the AD8330 in single ended input and output operation and I'm not able to get the full range out of the device. Beyond 1.2V on VDBS the gain starts decreasing.  Is the range impacted by single ended operation?  The datasheet doesn't have much info on single ended mode.


In my setup, the input signal from a VNA is going to INHI and I'm measuring OPHI with the same VNA.  I've attached the gain response from 0-1.2V.  The response is 6dB lower than the curve given in the datasheet, which matches what the datasheet says should happen.   However, I was thinking that I should be able to increase VDBS to 1.5V achieving 43dB gain.  I should mention that I have INLO grounded.  Not sure if that is ok or if it has an impact.  It says in the datasheet that: 


The unused pin must be connected either through a capacitor to ground, or through a dc bias point that corresponds closely to the dc level on the active signal pin.


The DC level on the active pin is zero, so I grounded the pin.  If I use a capacitor, what value do you recommend?  Will it impact the bandwidth?