ad8310: Level shifting the output

Document created by analog-archivist Employee on Feb 23, 2016
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I have the same circuit like the AD8310 evaluation board. I need 150mV at the
pin 4 (out) max when I close the RF In. I got 0.4V when I close the RF In. 

Can you please send to me solution/application for offset? 

I tried to work with the OFLT pin the best results (0.4V_was at 1.9V. 

 

The output voltage of the AD8310 is approximately 0.4V to 2.6V which is simply
defined by the headroom of the output stage.

A simple op amp circuit connected to the AD8310 output can apply a gain and
offset correction to this output signal so that the signal levels for mimimum
and maximum received signal level correspond to the requirements of the
following stage.

You can use the circuit shown in the data converter handbook
http://www.analog.com/library/analogDialogue/archives/39-06/data_conversion_hand
book.html

Chapter 6 page 6.11 figure 6.10A. If you don't have the appropriate low
impedance Vref available, you can replace R1 with a resistive divider (R1a and
R1b) between the supply and ground. R1a goes from the inverting input to
Vsupply and R1b goes from the intverting input to ground.

(R1a x R1b)/(R1a+R1b) = R1 (for the calculations of signal gain in figure 6.11
to remian true.)

Vref = Vsupply x R1b/(R1a + R1b)

The OFLT pin is for the on-chip high pass filter bandwidth setting, and cannot
be used to level shift the AD8310 output.

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