面向声学芯片的三阶反比例级联运放设计与仿真OA

As the core signal conditioning unit in surface acoustic wave(SAW)sensing systems,integrated operational amplifiers critically determine system performance by their gain and bandwidth characteristics.Targeting the limitations of conventional designs for 315 MHz delay-line SAW sensors,this work proposes a high-performance two-stage CMOS operational amplifier leveraging a third-order inverse proportional cascade structure to enhance gain and bandwidth.A multi-stage Miller compensation scheme is implemented to reshape the zero-pole configuration in the operational amplifier's transfer function,achieving enhanced phase margin and robust system stability.Experimental results show that the designed operational amplifier has a DC gain of 127.8 dB,a unity gain bandwidth of 906.7 MHz,and a power consumption of 20.2 μW,and its phase margin can reach 108.7°.The design achieves 37 dB gain at 315 MHz,meeting the oscillation loop requirements for SAW delay-line sensors below 400 MHz.This design not only provides key technical support for the integration and high performance of acoustic sensing system,but also can be extended to high-frequency and low-power scenarios such as wireless sensor network(WSN),biomedical detection and industrial Internet of Things(IoT)terminals,so it has significant engineering application value.