ESD protection to overcome internal gate oxide damage on digital-analog interface of mixed-mode CMOS IC's

Abstract

This paper reports an ESD internal gate-oxide damage occurred on the digital-analog interface of a mixed-mode CMOS IC. A new ESD protection method is proposed to rescue this internal gate-oxide damage by adding ESD-protection devices on the long metal line between digital-analog interfaces. Experimental verification has confirmed that the IC product can be rescued to pass 2-KV ESD stress from the digital/analog VDD to digital/analog VSS pads without causing any internal damage again.