This paper describes the design of two power amplifiers (PA) for WLAN 802.11n fabricated in 65nm CMOS technology. Both PAs utilize 3.3V thick-gate oxide (5.2nm) transistors and employ a two-stage differential structure, but the input and interstage matching networks are realized differently. The first PA uses LC matching networks for matching, while the second PA uses on-chip transformers. EVM, output power levels, and spectral masks are obtained for a 72.2Mbit/s, 64-QAM 802.11n OFDM signal.