A Dynamically Biased Multiband 2G/3G/4G Cellular Transmitter in 28 nm CMOS

摘要

We present a highly configurable, low-power, low-area, low-EVM, SAW-less transmitter (TX) architecture that is based on a dynamically biased power mixer. All FDD/TDD bands from 0.7 to 2.7 GHz for 4G LTE Rel-11 and 3G 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. Dynamic biasing leads to greater than 50% current savings when compared to fixed-biasing while providing a higher output power with better linearity. Implemented in 28 nm CMOS technology, the TX shows better than RX-band noise emission and ACLR for output powers up-to across all 3G/4G bands, while demonstrating above 80 dB of gain control range. In addition, the TX can be configured to provide better than CIM3, allowing it to meet stringent spurious emission specifications when transmitting 1 RB 4G LTE signals in B13/B26/B1.