ESD protection circuit using zener diode and interdigitated NPN transistor

摘要

The present invention provides a high efficiency ESD circuit that requires less space through uniform activation of multiple emitter fingers of a transistor structure containing an integral Zener diode. The Zener diode is able to lower the protection circuit trigger threshold from around 18 volts to around 7 volts. This method minimizes series impedance of the signal path, thereby rendering an NPN structure that is particularly well suited for protecting bipolar and CMOS input and output buffers. The ESD circuit of the present invention provides a relatively low shunt capacitance (typically <0.5 pF) and series resistance (typically <0.5 ohm) that are desirable for input and output circuits of present and future contemplated generations of sub-micron bipolar/BiCMOS circuit processes.