A 2.4 GHz TX in 65 nm CMOS defines three channels using three high- FBARs and supports OOK, BPSK and MSK. The oscillators have 132 dBc/Hz phase noise at 1 MHz offset, and are multiplexed to an efficient resonant buffer. Optimized for low output power 10 dBm, a fully-integrated PA implements 7.5 dB dynamic output power range using a dynamic impedance transformation network, and is used for amplitude pulse-shaping. Peak PA efficiency is 44.4% and peak TX efficiency is 33%. The entire TX consumes 440 pJ/bit at 1 Mb/s.