A 2.4 GHz TX in 65 nm CMOS defines three channels using three high-Q FBARs and supports OOK, BPSK and MSK. The oscillators have -132 [dBc over 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 over bit] at 1 [Mb over s].Focus Center Research Program. Focus Center for Circuit & System Solutions. Semiconductor Research Corporation. Interconnect Focus Center