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ADRF6518 Is it possible to control the output offset?

Question asked by HenkP on Jun 8, 2015
Latest reply on Jun 9, 2015 by HenkP

In a DC-coupled signal chain I planned to implement the ADRF6518.

The analogue gain control will be used especially in the first stage before the filtering.

I assume the gain will be controlled with the mid-range as reference: gain will be adjusted symmetrical for the positive and negative side of the signal.

The signal to be processed however will be asymmetrical. The signal margins in the ADRF6518 will be enough to process it.

At the end I like to send the differential output of the ADRF6518 to the differential input of an ADC. Doing it directly I will miss almost one bit of the resolution of the ADC.

 

So my question is : Can I (mis-)use the OFS1 / OFS2 connections (intended use: to connect "Offset Correction Loop Compensation Capacitors") to control with a connected DC level the offset of the output of the ADRF6518?

 

If the output impedance of the offset measurement amplifier (sie fig 71 of the data sheet) is known and has a reasonable value, then it would be possible to connect an external offset control DC signal to it and so controlling the output offset.

 

Looking forward to your suggestions.

 

best regards,

Henk

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