In order to improve the in-band gain and bandwidth of operational amplifiers,a four-stage operational amplifier of the broadband Δ-Σ ADC used in long-term evolution receivers is proposed.In the operational amplifier,a hybrid frequency compensation scheme combining feedforward Gm-C and Miller technique is adopted to ensure the stability.Then,a high-performance four-stage operational amplifier is designed in 0.13 μm 1P6M CMOS technology,and it is applied to the broadband Δ-Σ ADC.Test results show that ( 1) with a power supply of 1.5V,the operational amplifier achieves a unity gain bandwidth of 442MHz,a DC gain of 72.8dB and a slew rate of 101V/μs; ( 2) with the same bandwidth and power dissipation,the in-band ( 0 ～ 10MHz) gain of the proposed amplifier is 6 dB more than that of the traditional two-stage operational amplifier; and ( 3) in a signal bandwidth of 10MHz,the broadband Δ-Σ ADC adopting the proposed amplifier achieves a SNR of 68 dB and a SFDR of 78 dB.