ESD Protection

[Charles Linquis]

PICs are pretty tough, but I design a lot of military stuff that has to pass ESD testing. This is my checklist of things to do - and it has always proven successful. I have drawn sparks to the PCB several times, and the PIC didn't even reset.


On all inputs where signals come from "off the board" either buffer the input
with a logic gate or put a 2K resistor in series with the input pin and a .01uf cap from the pin to GND.

Buffer all outputs that go "off the board" with logic or transistors.

Make sure MCLR is pulled up to VCC with a 4.7K (or smaller) resistor. Keep this line short.

Use a 4 layer (or more) PCB with power and GND planes.

Use 4 .1uF and 2 10uF low-ESR tantalums across the power pins.

Put a reverse-biased diode across the power pins.

Use a 7V TRANSZORB across the power pins.

Keep the lines to the crystal very short.

[precision]

and keep your running project in microwawe
high microwawe
pause 1000
low microwawe
if pic is safe THEN
your project is safe from ESD
ELSE
Keep more prtection From ESD
ENDIF

[schlaray]

I thank everyone for their input. Along with ESD protection I should have included any and all other sources of distruction. Lightning strikes and an industrial type enviorment should have been included. Many years ago I lost an IBM Aptiva computer when there was a strike close to my home. All other electronic equipment survived.