What countermeasures should be taken for signals with a low slew rate (signals with slow input rise and fall times)is input?

In most cases, putting a product with a Schmidt trigger function on the input will solve the problem. Products without a Schmitt trigger function on the input may experience chattering due to low slew rate signals.

Schmitt trigger function has a hysteresis voltage VH between the input High level threshold voltage VP and Low level threshold voltage VN. Therefore, even if noise enters the signal when the input transitions from Low to High, it will not become High unless the voltage of VP is exceeded. In addition, once it becomes High, it will remain High even if the voltage drops slightly, unless it drops below VN. In this way, chattering, which is a problem with signals with a low slew rate (also known as signal slow input when the input rise/fall time is slow), is less likely to occur. (Refer to Fig. 1)

Fig. 1 Schmitt Inverter
Fig. 1 Schmitt Inverter

Related Links

The following documents also contain related information.

Product Lists

FAQs

Application Notes

Product page General Purpose Logic ICs
Products
e-Learning Basics of CMOS Logic ICs
e-Learning
e-Learning Usage Considerations of CMOS Logic ICs
e-Learning

Back to FAQs of General-Purpose Logic ICs

開啟新視窗