An electrostatic discharge (ESD) protection device includes a semiconductor substrate comprising a buried insulator layer and a semiconductor layer over the buried insulator layer having a first conductivity type, and first and second bipolar transistor devices disposed in the semiconductor layer, laterally spaced from one another, and sharing a common collector region having a second conductivity type. The first and second bipolar transistor devices are configured in an asymmetrical arrangement in which the second bipolar transistor device includes a buried doped layer having the second conductivity type and extending along the buried insulator layer from the common collector region across a device area of the second bipolar transistor device.