Protection against static

[Urahara]

Hi

I have 8 pins from a PIC MCU wired to a RJ45 as connection to the outside world via sensors (LDR, LM35, etc). Some of the 8 pins are used as inputs, the rest as outputs.

Some questions:
1)Is it advisable and necessary to put in static protection? I am talking abt those generated when you drag your feet against a carpeted floor and then touching the door knob, for example.

2)Is it true that I only need to protect those pins configured as input pins? or output pins would also need to be protected?

3) Am thinking of using a pair of schottky diodes for input pin protection. see attached. got the idea from **broken link removed**. Would it be the same if output pins need to be protected too?

Thks!

 

[Nigel Goodwin]

PIC's already have such protection diodes internally, on almost all I/O pins.

 

[Urahara]

sounds good!

how abt my query abt protection of output pins? is it necessary, assuming the IC does not hv protection diodes like the PIC?

 

[Nigel Goodwin]

sounds good!

how abt my query abt protection of output pins? is it necessary, assuming the IC does not hv protection diodes like the PIC?

Pins are both input and output, so both have them.

 

[ericgibbs]

Some documents recommend a low value series resistor in series with an input pin in order to limit the current thru the internal protection diodes, say a 220R.

 

[Urahara]

thks! will try that out.