A 2.4GHz TX in 65nm CMOS defines three channels using three high-Q FBARs and supports OOK, BPSK and MSK. The oscillators have -132dBc/Hz phase noise at 1MHz offset, and are multiplexed to an efficient resonant buffer. Optimized for low output power ≈-10dBm, a fully-integrated PA implements 7.5dB 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 440pJ/bit at 1Mb/s.