This paper presents a bulk CMOS power amplifier targeting enhanced mobile broadband (eMBB) in 5G New Radio (5G NR). To realize a wideband OFDM and high linearity PA, a ladder-transformer network with second-order harmonic traps is proposed in this paper. Fabricated and designed in 28nm CMOS LP under 1 V supply, the two-staged PA is aimed at 28 GHz with class-AB operation. The designed PA measured continuous wave (CW) signal performance at 28 GHz with small-signal gain 18.5 dB, Psat 18.9 dBm and PAEmax 39.7%. As for modulated signal, with stringent 9.6dB PAPR 64-QAM OFDM signal, the PA supports up to 1.2GHz RFBW with high Pout, avg/P eof 9.3dBml10.3% and 4.32 Gb/s data rate. 5G-NR 64-QAM OFDM signals at 28GHz with non-contiguous 2CC scenarios are also shown in this paper.