the present invention relates to an ic substrate provided with over voltage protection functions and thus , a plurality of over voltage protection devices are provided on a single substrate to protect an ic chip directly . according to the present invention , there is no need to install protection devices at respective i / o ports on a printed circuit board to prevent the ic devices from damage by surge pulses . therefore , the costs to design circuits are reduced , the limited space is efficiently utilized , and unit costs to install respective protection devices are lowered down .