●Hello,and welcome to the TI Precision Lab supplement for op amp stability.●This lab will walk through detailed calculations,SPICE simulations,and real-worldmeasurements that greatly help to reinforce the concepts established in the stability video series.●你好，欢迎来到TI Precision Labs（德州仪器高精度实验室）的运放稳定性环节。
●这个实验会包括计算，SPICE仿真和实际测试。
这些环节帮助大家对视频中的概念加深理解。
●The detailed calculation portion of this lab can be done by hand,but calculationtools such as MathCAD or Excel can help greatly.●The simulation exercises can be performed in any SPICE simulator,since TexasInstruments provides generic SPICE models of the op amps used in this lab.However,the simulations are most conveniently done in TINA-TI,which is a free SPICE simulator available from the Texas Instruments website.TINA simulation schematics are embedded in the presentation.●Finally,the real-world measurements are made using a printed circuit board,orPCB,provided by Texas Instruments.If you have access to standard lab equipment,you can make the necessary measurements with any oscilloscope, function generator,Bode plotter,and±15V power supply.However,we highly recommend the VirtualBench from National Instruments.The VirtualBench is an all-in-one test equipment solution which connects to a computer over USB or Wi-Fi and provides power supply rails,analog signal generator and oscilloscope channels,and a5½digit multimeter for convenient and accurate measurements.This lab is optimized for use with the VirtualBench.●本实验的计算可以通过實際計算，如果使用Mathcad或者Excel这样工具会更好。
●仿真环节可以使用任何SPICE仿真器，因为在本实验中提供的是德州仪器提供通用的运放的SPICE的模型。
用TINA-TI实施这些仿真是最方便的。
TINA 是免费的SPICE仿真器，可以从TI的网站上下载。
TINA仿真原理图会附在PPT中。
●最后，真实的测试会使用TI提供的印刷电路板。
如果你有标准的实验设备，可以用示波器，波形发生器，波特仪和±15V电源来进行测试。
我们推荐使用国家仪器的虚拟仪器。
这套虚拟仪器是一套多功能集成设备，可以通过USB或者WIFI与电脑连接。
这台仪器提供电源，信号发生器，示波器和5位半的万用表，方便进行精确测试。
本实验因搭配使用虛擬儀器而優化電路量測。
●In experiment1,we’ll determine the phase margin,and therefore the stability,ofa buffer circuit which is being used to drive a large capacitive load.We’lldetermine the phase margin by observing the transient overshoot as well as the AC transfer characteristic.●在实验1，我们会决定带大电容负载的缓冲电路的相位裕度和稳定性。
我们也会通过观察瞬态的过冲和AC传输特性来确定稳定性。
●First,calculate the phase margin and percentage overshoot for the circuit shownhere,using the techniques and equations given in the stability e the plots given on the next slide.●首先，使用稳定性章节中的公式和方法来计算这里所示电路的相位裕度和过冲量。
图形会在下一页给出。
●This circuit uses the OPA277.In order to perform the calculations,you need toknow the percent overshoot versus load capacitance for that device,shown on the top left.Then,use the plot on the right to determine the phase margin from that percentage overshoot.●Enter your answers in the table at the bottom of the slide.The solutions arealready provided to allow you to check your work.●这个电路使用OPA277，为了计算过冲及相位裕度，你必须知道这颗元件过冲程度和容性负载的关系，如左上图所示。
再使用右图来确定相位裕度和过冲的关系。
●你可以在ppt下面的表格中输入你的答案。
这个可以用来检验你的结果。
●The next step is to run a SPICE simulation analysis for the transientovershoot.The necessary TINA-TI simulation schematic is embedded in this slide set–simply double-click the icon to open it.To run the analysis,click Analysis Transient,and run the analysis from100us to250us.The input is a20mVpk, 10kHz square wave.●下一步是进行SPICE的暂态过冲仿真。
TINA的仿真电路图附在ppt中，双击图标即可打开。
仿真步骤如下：点Analysis Transient。
仿真时间从100us 到250us。
输入信号为20mVpk，10kHz方波●You should see a result similar to e the simulated percentage overshootof40%to calculate the phase margin,which comes out to31degrees.●你可以通过仿真得到和上图相似的结果。
仿真得到的40%的过冲可以换算成31度的相位裕度。
●Next,run a SPICE simulation analysis for the AC transfer characteristic.This willallow us to see the op amp’s AC peaking,which is another indicator of phase margin.●Use the same TINA-TI simulation schematic as before.To run the analysis,clickAnalysis AC Analysis AC Transfer Characteristic.Run the analysis from10kHz to10MHz.●接下来，进行AC传递函数的SPICE仿真分析。
这可以让我观察运放的AC起翘（peaking）,这是表征相位裕度的另一个指标。
●使用和之前一樣的TINA的原理图。
点击click Analysis AC AnalysisAC Transfer Characteristic进行仿真。
仿真频率从10kHz到10MHz●You should see a result similar to this.The6.7dB of simulated AC peaking resultsin a phase margin of approximately27degrees.●你可以看到一个相似的仿真结果。
仿真得到的6.7dB AC起翘得到27度的相位裕度。
●Make sure to disable the DC power supply before setting up the test PCB!In theVirtualBench software,click the power button in the DC Power Supply area to turn off the power.Check the front panel of the VirtualBench unit to make sure the LEDs are OFF!Also ensure that the function generator is OFF.●測試電路之前,請先確定直流電源是關閉的.在虛擬儀器軟體中,點擊電源按鈕關閉電源,觀察前面板的發光二極體是關閉的已確定電源關閉.訊號產生器也必須是關閉的.●To prepare the test board for the measurement,install the jumpers and deviceson circuit5as shown here.Install JMP17,JMP18,JMP19,JMP20,JMP48,and JMP50,as well as the OPA277in socket U7.●为了准备测试用的测试板，按图所示安装电路5的跳针和器件。