The devices are designed to protect the capacitive loads of Input/Output (I/O) ports (such as USB 2.0, Ethernet, Digital Visual Interface (DVI), etc.) from being damaged by ElectroStatic Discharge (ESD). To provide ESD protection to downstream signal and supply components, the devices incorporate four pairs of ultra low capacitance rail-to-rail diodes plus two Zener diodes. This provides protection against contact discharge voltages as high as ±8 kV in accordance with IEC 61000-4-2, level 4. The ESD protection is independent of the supply voltage due to the rail-to-rail diodes being connected to a Zener diode. The devices are fabricated using monolithic silicon technology and integrate four ultra low capacitance rail-to-rail ESD protection diodes plus two Zener diodes.