论文部分内容阅读
本设计实例描述了一种简单的方法,可以用一只无缓冲CMOS六反相器HD14069UB(参考文献1),做出四种测试件:一个有良好定义逻辑电压窗口的逻辑笔,输入阻抗约为1MΩ;一个开路测试仪,上限电阻可以从几十欧到几十兆欧;一个单脉冲或脉冲串注入器或简单的信号发生器;还有一个是高阻音频探头。使用一只4069中的六个反相门、两或三只电阻,以及少许无源元件,就可以做出这些测试仪器。在双门构成的CMOS/TTL兼容探头中,R1至R4电阻网络对反相器输
This design example describes an easy way to make four test pieces with an unbuffered CMOS six-phase inverter, the HD14069UB (Reference 1): a logic pen with well-defined logic voltage window, input impedance of about 1MΩ; an open circuit tester, the upper resistance can be from tens of ohms to tens of megohms; a single pulse or pulse train injector or a simple signal generator; there is a high impedance audio probe. These test instruments can be made using six inverting gates in a 4069, two or three resistors, and a few passive components. In a two-gate CMOS / TTL-compatible probe, the R1 to R4 resistor network is connected to the inverter