US Patent 10211058 ESD protection device

An electrostatic discharge protection device includes a buried layer having a plurality of heavily doped regions of a first conductivity type and a laterally diffused region between adjacent heavily doped regions, a semiconductor region over the buried layer, and a first well of the first conductivity type extending from a surface of the semiconductor region to a heavily doped region. The device includes a first transistor in the semiconductor region having an emitter coupled to the first terminal, and a second transistor in the semiconductor region having an emitter coupled to the second terminal. The first well forms a collector of the first transistor and a collector of the second transistor.