A fully digital PWM-based 1 to 3 GHz multistandard transmitter in 40-nm CMOS

A fully digital 1 to 3 GHz multimode transmitter is presented which contains two RF modulators: One uses baseband (BB) PWM, while the other uses RF PWM. RF PWM produces less harmonics, while BB PWM has a higher dynamic range (DR) and consumes less power. The BB PWM system satisfies the WLAN EVM limit over the whole frequency range. The RF PWM system achieves sufficient EVM for standards such as EDGE and WCDMA. Both systems support the use of multiple PAs to extend the DR using multilevel PWM.