A 1.1V 5-to-6GHz reduced-component direct-conversion transmit signal path in 45nm CMOS

This paper introduces one of the first reported transmit signal chains in a 45 nm CMOS process operating from a 1.1 V supply with performance compatible for long-range, wide-bandwidth, high-data rate standards. A new scheme to reduce the number of components in the signal path and enhance the TX-chain linearity for use in 4G OFDM based systems is presented. A traditional direct-conversion signal path contains a filter, VGA and mixer stage. The proposed transmitter combines the functions of the three aforementioned blocks into a single component, as described in the first section of this paper (note: only one filter pole is combined, additional poles must be added as needed). The overall transmitter is then described, followed by measured data to demonstrate performance commensurate with operation as a general purpose device, in a co-existence environment.