My projects are not very complex. One microcontroller (64 pins) with interfaces (OC input/output, relays output, Ethernet, RS485, RFID, ZigBee, LCD, touch pannel, touch keyboard) powered by DCDC accepting input 8…30V (assuming overvoltages up to 50V (33V transils)).
I think such error is 0,01% chance. When you draw elements around that IC you see its application in datasheet. My microcontroller has many pins which I left unconnected (in one device I used all and it is a problem) and not using ERC I just left them without any my action.
May be my thinking is because:
- when I begun I had no access to PCB software (painted PCB by hand) so no ERC possible.
- when we start to use Protel someone else worked with it and I gaved him ballpen drawn schematics and then get it printed to verify,
- when I took designing PCB (because of EMC) I have never found ERC (used only functions needed and never serched for others - I concentrated on PCB and not on schematic where I didn’t know of any problems possible).