Input Connection

[JohnsonMiller]

Hi Guys,

I heard that connecting input pin directly to GND or VDD is not correct, and recommend using a resistor in series. I have seen design from TI, doing this. With almost all of IC design in CMOS I am interested to know the technical background. Why not to connect input directly to GND?

BR,

[robertferanec]

I have never heard anything like that. Very often you can find in reference schematics e.g. Enable pins connected directly to power.

However, I almost never connect input pins directly to VCC or GND and I often put there a resistor just in case I need to disconnect the signal and also, it will help you to limit currents flowing inside the pin.