Protection measures for operational amplifier differential mode voltage breakdown input stage

The overvoltage protection circuit without internal protection measures is shown in Figures (a) and (b). Figure (a) is a diode protection circuit, and Figure (b) is a voltage regulator protection circuit. In specific applications, it is sufficient to select one of them. The resistor in the figure is a current limiting clamp resistor. Its value is as high as 10kΩ and will not reduce the offset voltage. In practical applications, the input end of the resistor may be the signal input end. Usually, in order to improve DC accuracy, it is hoped that each input port branch is connected to an equal resistor. In some cases, as long as the input resistor and the feedback resistor can limit the current of the clamp diode, one or two resistors can be omitted.