LMS6002D, why the use of three RX ports?


#1

Hello everyone!

Greetings from Rapido Project.

The team is wondering why the LMS6002D transceiver has three rx ports? Two for narrow band, and one for Broad band.

What’s is the difference of using these three ports more than in the bandwidth that you can obtain from it. It is because the type of application where this chip can be used?

Thanks in advance,


#2

Hello,

Please see page 3 of the datasheet:

http://www.limemicro.com/download/LMS6002Dr2-DataSheet.pdf

This details the frequency range for each of the 3x LNA inputs and their impedance.

Regards,

Andrew


#3

Short answer: frequency banding.

It’s REALLY HARD to make a receive path that is flat in frequency response from e.g. 1MHz to 3GHz. Also, if the signal you are interested in is at 100MHz, you really don’t want al the crap from 400MHz - 3GHz coming in and killing your sensitivity. So, chips like this are usually designed with multiple inputs, with the idea being that the different ports will set up with different preselectors to allow optimal operation in the band of interest. For example, a device being used in cellular might have one port set for around 900MHz, and the other around 1.9GHz, with the wideband ports being used for things like WiFi at 2.4GHz.


#4

@N0YKG that’s the kind of answer that I wanted.

Thanks a lot for your accurate answer.