| 摘要 |
A bi-directional protection device includes a bi-directional NPN bipolar transistor including an emitter/collector formed from a first n-well region, a base formed from a p-well region, and a collector/emitter formed from a second n-well region. P-type active regions are formed in the first and second n-well regions to form a PNPNP structure, which is isolated from the substrate using dual-tub isolation consisting of an n-type tub and a p-type tub. The dual-tub isolation prevents induced latch-up during integrated circuit powered stress conditions by preventing the wells associated with the PNPNP structure from injecting carriers into the substrate. The size, spacing, and doping concentrations of active regions and wells associated with the PNPNP structure are selected to provide fine-tuned control of the trigger and holding voltage characteristics to enable the bi-directional protection device to be implemented in high voltage applications using low voltage precision interface signaling. |
