Good advice as usual from mem.
My personal preference would be to use catcher diodes to the supply rails as in :-
http://www.thebox.myzen.co.uk/Tutorial/Protection.html
Given N engineers there will always be at least N+1 firmly held opinions. 
Good advice as usual from mem.
My personal preference would be to use catcher diodes to the supply rails as in :-
http://www.thebox.myzen.co.uk/Tutorial/Protection.html
Given N engineers there will always be at least N+1 firmly held opinions.