Passive transmitter architecture with switchable outputs for wireless applications

摘要

A transmitter architecture having a single signal path or hardware to cover WCDMA/EDGE/GSM applications, and requires no SAW at the transmitter outputs. The transmitter architecture allows for a transmit convergence feature. A passive mixer with unique driver and furthermore using native devices available from the CMOS process for the mixer cores enables low voltage and low power design, low output noise and high linearity. A digital variable gain amplifier has the capability to cover wide output dynamic range operated from low supply voltage and interfaced digitally with the baseband circuit without DAC. A single transformer is used to combine the outputs from the WCDMA/EDGE and GSM drivers and subsequently convert the differential signal paths into a single-ended signal. RF switches are used to divert the output from the transformer to different bands and applications.