Selecting a IQ demodulator for a SDR

[pisoiu]

I am trying to design a SDR USB stick to cover 0-200mhz range. I have some troubles with selecting a proper IQ demodulator for this range, can anyone recommend a suitable IC or a combined solution (demodulator+VGA, etc). Many of iq demods from Analog Devices or Linear does not cover this range, they are dc-50mhz or those which cover higher frequencies does not cover DC.
Thank you in advance.

/pisoiu

 

[mtwieg]

I doubt you'll find any single chip solutions that cover that range.

How are you planning on generating an LO with such a large range? A DDS? If so you could use a dual channel DDS (AD9958) and generate quadrature LOs directly, then you just need a couple broadband active mixers (I know analog makes a couple).

 

[pisoiu]

Not sure about LO yet, one choice would be SI570, even if it starts from 10Mhz.

 

[vfone]

You can try LTC5584 which works form 30MHz to 1.4GHz, but LTC claims that works down to 10MHz with some decrease of performance. Depending by application, is possible to be fine.

https://www.linear.com/product/LTC5584

 

[pisoiu]

The main problem with starting freq. is that I want to cover ham bands below 10mhz, 160, 80 and 40m. Thanks for suggestion.