Differential IF amplifier for transmitter

Hi,

I am designing an LTE transmitter using the two-step architecture. I need a differential IF amplifier after DAC output. The IF frequency is 164MHz, bandwidth is 20MHz, it will be followed by an IF SAW filter, then again a differential IF amplifier to drive the up-conversion mixer. I plan to use 50ohm for the impedance match.  I searched ADI website. It seems all differential IF amplifiers from Analog Device is designed with ADC interference in mind. Can I use those in my design?

Thanks,

George

Parents
  • 0
    •  Analog Employees 
    on Oct 3, 2013 12:34 AM

    Sounds like you need an amplifier with real input and output impedances (e.g. vs. an amplifier with relatively high input impedance and low ouitput impedance).  Take a look at AD8352 which has fixed pin-strapped gain or AD8375 which has digitally programmable gain and can be configured to have 150 ohm input and output impedance. A devices like ADL5565 could also work but its output impedance is low. So you might have to add (lossy) output series resistance to provide matching to your next stage. Do you really need to match to 50 ohms throughout the circuit?

Reply
  • 0
    •  Analog Employees 
    on Oct 3, 2013 12:34 AM

    Sounds like you need an amplifier with real input and output impedances (e.g. vs. an amplifier with relatively high input impedance and low ouitput impedance).  Take a look at AD8352 which has fixed pin-strapped gain or AD8375 which has digitally programmable gain and can be configured to have 150 ohm input and output impedance. A devices like ADL5565 could also work but its output impedance is low. So you might have to add (lossy) output series resistance to provide matching to your next stage. Do you really need to match to 50 ohms throughout the circuit?

Children
No Data