Apparatus for transceiver signal isolation and voltage clamp

摘要

An apparatus for transceiver signal isolation and voltage clamp from transient electrical events includes a bi-directional protection device comprising a bipolar PNPNP device assembly, a first parasitic PNPN device assembly, and a second parasitic PNPN device assembly. The bipolar PNPNP device assembly includes an NPN bi-directional bipolar transistor, a first PNP bipolar transistor, and a second PNP bipolar transistor, and is configured to receive a transient voltage signal through first and second pads. The first and second pads are electrically connected to the PNPNP device assembly through emitters of the first and second PNP bipolar transistors. The bipolar PNPNP device assembly is electrically connected to a first parasitic PNPN device assembly comprising a parasitic PNP bipolar transistor and a first parasitic NPN bipolar transistor. The bipolar PNPNP device assembly is further connected to a second parasitic parasitic PNPN device assembly comprising the parasitic PNP bipolar transistor and a second parasitic NPN bipolar transistor. The base of the parasitic PNP bipolar transistor is connected to the substrate of the transceiver through a resistor to prevent triggering and breakdown of the first and second parasitic PNPN device assemblies.

主权项

1. An apparatus comprising:
a p-type substrate; a first n-type well region, a second n-type well region, and a first p-type well region configured to form an NPN bi-directional transistor formed in the p-type substrate; a first p-type active region disposed in the first n-type well region and a second p-type active region disposed in the second n-type well region; a p-type tub surrounding the NPN bi-directional transistor and in physical contact with the first n-type well region, the second n-type well region and the first p-type well region; an n-type tub surrounding the p-type tub; a p-type epitaxial region surrounding the n-type tub; wherein the first n-type well region, the p-type tub, and the n-type tub are configured to form a first parasitic NPN bipolar transistor; and wherein the p-type epitaxial region, the n-type tub, and the p-type tub are configured to form a parasitic PNP bipolar transistor.