WIDE BAND LNA WITH NOISE CANCELING

摘要

Techniques to improve low noise amplifiers (LNAs) with noise canceling are described. LNA includes a first (24) and a second (26) amplifier which work together to noise cancel the noise generated at an input stage circuit (22). The input stage circuit (22) receives an RF signal and is characterized by a first node and a second node. The first amplifier (24) converts a noise voltage at the first node into a first noise current at an output (220) of the first amplifier (24). The second amplifier (26) is directly coupled to the output of the first amplifier and provides noise canceling by summing the first noise current with a second noise current generated by the second amplifier as a function of the noise voltage at the second node. The proposed techniques eliminate the need for large ac coupling capacitors and reduce the die size occupied by the LNA.