INTEGRATED CIRCUIT Russian patent published in 1995 - IPC

FIELD: integrated circuit design. SUBSTANCE: integrated circuit has main and protective bipolar transistors of same type of conductivity built on semiconductor substrate. Base and emitter regions of main and protective transistors are formed in epitaxial layer. Collector region is common for both transistors. Second emitter region is formed in base region of protective transistor. High-alloyed regions of same type of conductivity as base regions covering bottom parts of emitter are formed under first and second emitters. Base-emitter regions of main transistor are connected, respectively, with first and second emitter regions of protective transistor. Electric characteristics of transistors comply with definite equations. EFFECT: provision for surge voltage protection of respective components of main transistor during its forward and reverse turn-on. 1 dwg