Resistor triggered electrostatic discharge protection

An integrated ESD protection device, having I/O and common terminals adapted to be coupled to I/O and common terminals of a core circuit being protected by the integrated ESD protection device, comprising:

• first and second bipolar transistors having a common collector region and comprising;
• first and second base regions of a first conductivity type, one base region for each bipolar transistor;
• a region of a second, opposite conductivity type extending beneath the first and second base regions, and separating and laterally surrounding the first and second base regions, and serving as the common collector region of the first and second bipolar transistors;
• a first emitter region of the second conductivity type within the first base region and a second emitter region of the second conductivity type within the second base region, wherein the first emitter region is adapted to be coupled to the common terminal of the core circuit and the second emitter region is adapted to be coupled to the I/O terminals of the core circuit;
• and
• first and second resistors coupled respectively between the emitter region and the base region of the first transistor and the emitter region and the base region of the second transistor, wherein the first and second resistors are located so that portions of the region of second, opposite, conductivity type are located between the first resistor and the first base region and between the second resistor and the second base region.

An ESD protection device adapted to be coupled between common and I/O terminals of a core circuit desired to be protected, comprising:

• one or more bi-directional resistor triggered ESD stages, each stage comprising:
• two bipolar transistors having a common collector and isolation region;
• a base region for each transistor separated by a portion of the common collector and isolation region;
• separate emitter regions, one in each base region;
• base contact regions, one for each base region;
• and
• ESD trigger resistors external to the transistors, coupled between the emitter region and the base contact region of each transistor.