Efficient protection structure for reverse pin-to-pin electrostatic discharge

摘要

An electrostatic discharge (ESD) protection structure for protecting against ESD events between signal terminals is disclosed. ESD protection is provided in a first polarity, by a bipolar transistor (4C) formed in an n-well (64; 164), having a collector contact (72; 172) to one signal terminal (PIN1) and its emitter region (68; 168) and base (66; 166) connected to a second signal terminal (PIN2). For reverse polarity ESD protection, a diode (25) is formed in the same n-well (64; 164) by a p+ region (78; 178) connected to the second signal terminal (PIN2), serving as the anode. The cathode can correspond to the n-well (64; 164) itself, as contacted by the collector contact (72; 172). By using the same n-well (64; 164) for both devices, the integrated circuit chip area required to implement this pin-to-pin protection is much reduced.