QUESTION

Question

Hello, looking for an app note for this part.  Of particular interest is LNA selection for the front end.  The drawing on the data sheet illustrates the RF in port connected directly to the antenna.  Have LNAs been used to improve performance?  If so, do any docs that you can share exist?

Thank you

Answer 1

Hi Chuckp,

M10578-A3 has LNA and SAW filter integrated, as shown in the block diagram on p.3 of the data sheet. We have found an additional LNA in most cases may only introduce a small increase in performance, also if the gain is too high it may introduce saturation; the integrated LNA gain is 18dB, if the external LNA is >16dB it will saturate the MTK receiver. For maximum performance, it's better focus on the antenna and good RF layout. We are happy to support you on your design/implementation, it is a standard service we offer to all of our customers free of charge. Please contact techsupport@antenova.com and let us know which country you are based in, so we can put you in touch with your regional representative.

Many Thanks

Steve

Comments

Thank you for your prompt response Steve.  How do I add another engineer (Michael Walker; ) to this thread?  He may want to follow up with more inquiries.  Please let me know

Thanks again.

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Hi chuckp,

Unfortunately we don't have this facility. However, for more complex questions you can contact techsupport@antenova.com and we will put you in touch with your regional support engineer.

Many Thanks

Steve

Answer 2

Hi, 

I believe you mean has the 2nd stage integrated LNA been used to improve the receiver. In this case i would say yes as having a second stage not only improves the overall power in for line of site satellites but will greatly improve the sensitivity for lower CN values enabling more visible SV. If you integrate into a device with cellular function then you should consider a external 2nd SAW to improve isolation.

Peter