AnsweredAssumed Answered

Output Power on FMCOMMS3

Question asked by rgetz Employee on Feb 11, 2015
Latest reply on Feb 11, 2015 by rgetz

Someone on the FMCOMMS3 product page:

http://www.analog.com/en/evaluation/eval-ad-fmcomms3-ebz/eb.html#buy

 

Someone made the comment:

 

Power o/p is not as claimed in data sheet. and i tried all the way to get o/p power more than -15 dBm on 400 Mhz, but not able to achieve.


The output power of the chip does not include the loss of the transformer on the FMCOMMS3 board. The -15dBm number is expected, and is shown in the performance metrics we have:

 

http://wiki.analog.com/resources/eval/user-guides/ad-fmcomms3-ebz/hardware/card_specification

 

specifically --

 

AD-FMCOMMS3-EBZ Specifications [Analog Devices Wiki]

 

This is due to the mini circuits transformer. (1-2 dB of insertion loss) and the 330nH inductors which are used to help power the Tx side.

http://www.minicircuits.com/pdfs/TCM1-63AX+.pdf

 

by changing those inductors - power at 400MHz can go up, but then it will drop worse than it does at 6GHz.

 

I'm sure that Tomas can comment more as well.

 

-Robin

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