Linearization of monolithic LNAs using low-frequency low-impedance input termination

This work investigates the linearization technique based on terminating the LNA input with low impedance at the low frequencies of the second-order mixing terms. This technique is analyzed using the Volterra series and is shown to be very effective in linearizing BJTs but not FETs if the latter are biased in the strong inversion region. Several methods to generate the low-frequency low-impedance input termination are reviewed. A SiGe BiCMOS cellular band CDMA LNA using this linearization technique is described. The LNA achieves +11.7dBm IIP3, 15.7dB gain and 1.4dB NF with a current consumption of only 3.9mA@3V.