US Patent 7136268 Tunable ESD trigger and power clamp circuit

A circuit and a method for the electrostatic discharge protection of integrated circuits. The electrostatic discharge protection circuit, including: an electrostatic discharge protection circuit, comprising: a first bipolar transistor coupled between a first circuit node and a second circuit node, the first bipolar transistor having a non-uniform subcollector region geometry, the first bipolar transistor having a different value for collector to emitter breakdown voltage than a value for collector to emitter breakdown voltage of an otherwise identical bipolar transistor having a uniform subcollector region geometry.