A dynamically-biased 2G/3G/4G multi-band transmitter with > 4dBm Pout, < −65dBc CIM3 and < −157dBc/Hz out-of-band noise in 28nm CMOS

Abstract

We present a highly-configurable, low-power, low-area, SAW-less TX architecture that is based on a dynamically-biased power mixer. All FDD/TDD bands for 4G LTE and 3G WCDMA/HSPA are supported in addition to 2G quad bands. The power-mixer bias current is dynamically adjusted based on the instantaneous baseband signal swing using a fully-differential hybrid full-wave rectifier / envelope detector circuit. Implemented in 28nm CMOS technology, the TX shows better than -157dBc/Hz RX-band noise emission and -41dBc ACLR for output powers up-to 4dBm across all 3G/4G bands. In addition, the TX can be configured to provide better than -65dBc CIM3, allowing it to meet stringent spurious emission specifications when transmitting 1RB 4G LTE signals in B13 / B26 / B1.