A robust digital predistortion (DPD) technique utilizing negative feedback itera-tion is introduced for linearizing power amplifiers (PAs) in long term evolution (LTE)/5G sys-tems. Different from the conventional direct leing and indirect leing structure, the pro-posed DPD suggests a two-step method to identify the predistortion. Firstly, a negative feed-back based iteration is used to estimate the optimal DPD signal. Then the corresponding DPD parameters are extracted by forward modeling with the input signal and optimal DPD signal. The iteration can be applied to both single-band and dual-band PAs, which will achieve superior linear performance than the conventional direct leing DPD while having a relatively low computational complexity. The measurement is carried out on a broadband Doherty PA (DPA) with a 200 MHz bandwidth LTE signal at 2.1 GHz, and on a 5G DPA with two 10 MHz LTE signals at 3.4/3.6 GHz for validation in dual-band scenarios.