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AD8347 Lower Band Operation

Does anyone have any idea whether or not the AD8347 I/Q Demodulator might still operate at 600 MHz?

I fully realize the part isn't specified for that band but was hoping that there might be enough residual operation for it to work in my application. I'm assuming that the gain, noise figure, OIPs, etc will be roughly the same and that, if anything, the I/Q balance will be the problem.

I'd make the measurement myself but don't have an eval board and won't be able to get one in house before this information is needed (end of this week - January 27th).

I already understand all the caveats up front - the part isn't specified for this band and ADI absolves all responsibility for using the part outside the published specifications. Past that though, does anyone have any clue or inclination they can share about this?



  • Hello Mark,

    The AD8348 is a very similar part to the AD8347 and its operating range is from 50 MHz to 1000 MHz.  This falls within your 600 MHz operating range.  Will this be an alternative for you or do you have other restrictions which binds you to the AD8347?


  • The demodulator will be used in a wide-band receiver that must cover WMTS bands at 600 MHz and at 1400 MHz (although not simultaneouly).

    There is no one device that will cover both of these bands and I can't afford to use two different parts to cover the different bands. My only hope was that the AD8347 might do the trick since it's already specified to handle the upper band and comes close to covering the lower band. I was hoping the part had enough umph to actually operate below its specified frequency range.  

  • Hello Mark,

    You can take a look at the ADL5380 which covers the frequency range from 400 MHz to 6 GHz.  This may be a potential solution for you.

    Concerning the AD8347, what determines the low end of the frequency range is the polyphase filter architecture.  Therefore, the quadrature accuracy will most definitely degrade when you try to operate the device lower than what it is spec-ed for. 


  • This question has been assumed as answered either offline via email or with a multi-part answer. This question has now been closed out. If you have an inquiry related to this topic please post a new question in the applicable product forum.

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    EZ Admin