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OPA2376: 共模电压会影响开环增益吗

Part Number: OPA2376

OPA2376 ,单电源供电的开环增益曲线figure1

At TA = 25°C, VS = 5 V, RL = 10 kΩ connected to VS / 2, VCM = VS / 2, and VOUT = VS / 2

当Vcm=0.01v,其也是满足器件要求的(手册上的共模电压范围是(V-)-0.1到(V+)+0.1V),仿真出来开环曲线是完全错误的,如图1。请教一下是什么原因?

Vcm=0.05V或0.1V,仿真出来开环曲线就和datasheet上的基本一致,如图2和图3。

附件是仿真文件

OPA2376_AOL.TSC

  • 您好,

    这应该与运放的输出范围有关,在输入10mV共模信号时,仿真电路的直流等效模型是电压跟随器,那么输出就是10mV,而10mV是运放的最小输出,如果输入端再叠加少量的输入失调电压,那么此时输出可能超出了输出范围,运放不再线性工作。我仿真11mV的共模电压是可以的,或者给运放VS- 供电管脚加一个小的负供电电压,仿真也是正常的。