Low noise amplifiers with transformer-based signal splitting for carrier aggregation

Abstract

Low noise amplifiers (LNAs) supporting carrier aggregation are disclosed. In an exemplary design, an apparatus (e.g., a wireless device, an integrated circuit, etc.) includes an amplifier circuit, a transformer, and a plurality of downconverters. The amplifier circuit receives and amplifies an input radio frequency (RF) signal and provides an amplified RF signal. The input RF signal includes transmissions sent on multiple carriers at different frequencies to a wireless device. The transformer includes a primary coil coupled to the amplifier circuit and a plurality of secondary coils providing a plurality of output RF signals. The plurality of downconverters downconvert the plurality of output RF signals with a plurality of local oscillator (LO) signals at different frequencies. Each downconverter includes a pair of mixers that receives one output RF signal and one LO signal and provides inphase and quadrature downconverted signals for one set of carriers being received.