IF sampling frequencies vs FPBW

On the first page of AD9265 datasheet, it mentions that "IF sampling frequencies to 300 MHz" and "Differential analog inputs with 650 MHz bandwidth”.  I think 650MHz is the 3dB full power BW, then we can input analog signal up to 650MHz. Right? How to understand "IF sampling frequencies to 300 MHz"? What's its meaning?

  • +1
    •  Analog Employees 
    on Aug 21, 2019 1:52 PM over 1 year ago


    Your understanding of the BW is correct and one could inject signals up to (and beyond) 650 MHz if the loss (3dB+) and performance degradation is considered acceptable for the application.  IF sampling is subjective since their are many RF bands situated below 300 MHz also.  That said..........many of the communication applications that may have used this device were high performance radio applications based on superhet architecture where the ADC would sample the IF signal following the mixer (after amplification and filtering).

  • Thank you for yor prompt reply. You mean 300MHz is hightlighted here just since it's a common used RF band.Right? For the signal up to 650MHz, it will even drop into 11st nyquist zone. How to guarantee its performances? It can still work well or we need to test in lab?