An electronic device includes a first-conductivity-type substrate and a second-conductivity-type epitaxial layer having a first dopant concentration. A first substrate region includes a second-conductivity-type buried layer and is enclosed by a first deep isolation structure. Within the first substrate region are a first doped region having the second conductivity type and a dopant concentration greater than the first dopant concentration and a second doped region having the first conductivity type. A second substrate region includes a first-conductivity-type buried layer and is enclosed by a second deep isolation structure. Within the second substrate region is a third doped region having the second conductivity type and a dopant concentration greater than the first dopant concentration.