Teensy 4.1 GPIO protection

[bdoan]

I am using a 4.1 as the controller in a test fixture.

I want to protect the GPIO pins against worst case faults (short to ground or short to 5V)

If I simply build out the output pins with 1.5K to limit the current, is that sufficient?

 

[msadie]

Absolute maximum rated voltage for T4.1 pins is 3.6V. if you expect the possibility of 5V, you will need something more to limit the voltage closer to 3.3V, like a zener or schottky clamp diode.

 

[BriComp]

Something like this:-

 

[bdoan]

Thanks

 

[MarkT]

But with Schottky diodes, not standard ones. You might also need to protect the 3.3V rail from rising above 4V with a zener clamp as well.