Drain-extended metal-oxide-semiconductor bipolar switch for electrical overstress protection

An electrical overstress switch for a high voltage interface, the electrical overstress switch comprising:

• a first terminal;
• a second terminal;
• a bipolar device comprising an emitter formed from an active region, a base formed from a semiconductor region of opposite doping type as the active region, and a collector formed from a well of common doping type as the active region, wherein the active region is electrically connected to the first terminal, and the well is electrically connected to the second terminal;
• an extended-drain metal oxide semiconductor (DEMOS) device comprising a drain formed from the well, a source formed from the active region, a body formed from the semiconductor region, and a gate formed from a gate region,
• wherein the gate region is formed over a field oxide region and the semiconductor region, and extends from an edge of the active region to an edge of the well;
• and
• a well ring surrounding the semiconductor region and of opposite doping type as the semiconductor region, the well ring and the semiconductor region configured to operate as a reverse protection diode device.

A system-on-a-package (SoP) comprising:

• a package substrate;
• and
• a system-on-a-chip (SoC) attached to the package substrate and configured to receive a high voltage supply and ground, wherein the SoC comprises:
• a high voltage interface circuit powered by the high voltage supply and ground;
• and
• an electrical overstress switch comprising an extended-drain metal oxide semiconductor (DEMOS) device and a bipolar device configured to protect the high voltage interface circuit from electrical overstress, wherein the bipolar device comprises an emitter formed from an active region, a base formed from a semiconductor region of opposite doping type as the active region, and a collector formed from a well of common doping type as the active region, wherein the DEMOS device comprises a drain formed from the well, a source formed from the active region, a body formed from the semiconductor region, and a gate formed over a field oxide region and the semiconductor region, and extending from an edge of the active region to an edge of the well, the electrical overstress switch further comprising a well ring surrounding the semiconductor region and of opposite doping type as the semiconductor region, the well ring and the semiconductor region configured to operate as a reverse protection diode device.