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A novel 3300V Trench IGBT with p-n-doped polysilicon split gate (PNSG-IGBT) is proposed for low EMI noise. The reverse-biased polysilicon PN junction is laterally depleted and charged by displacement current during the turn-off transient, which raises electrostatic potential in n-region of the polysilicon PN junction (VN) and electrostatic potential under the gate oxide (VACC) simultaneously. By TCAD simulation, during the turn-on transient, the maximum dVACC/dt is 57.1% lower than that of the SG-IGBT with the same RG and the excess VGE overshoot caused by reverse displacement current is effectively suppressed. Moreover, for the same EON, the maximum reverse recovery dVKA/dt of the FWD can be reduced by 77.3% and 30.7% compared with that of the FP-IGBT and the SG-IGBT respectively, which is of great merit in suppressing dV/dt noise. Consequently, the PNSG-IGBT shows less CM noise at high frequency, especially in the range of 20-40MHz.