An apparatus including an electrostatic discharge (ESD) protection device is disclosed. The ESD protection device includes a semiconductor having a first region (270), a second region (120) laterally surrounded by the first region (270), and a third region (130) laterally surrounded by the second region (120) to form a bipolar device. The first region (270) is doped with a first impurity of a first conductivity type and is separated from the second region (120) which is doped with a second impurity of a second conductivity type opposite the first type. A dimensional constraint of the regions defines an operational threshold of the ESD protection device. In one example, the separation between the first region (270) and the second region (120) defines a trigger voltage to cause the ESD protection device to become conducting. In another example, a width (310) of the second region (120) controls a holding voltage of the ESD protection device.
