Protection systems for integrated circuits and methods of forming the same

摘要

Harsh electrical environments integrated circuit protection for system-level robustness and methods of forming the same are provided. In one embodiment, a protection system includes dual-polarity high blocking voltage primary and secondary protection devices each electrically connected to a pad. The primary protection device has a current handling capability greater than a current handling capability of the secondary protection devices, and the secondary protection device has a turn-on speed that is faster than a turn-on speed of the primary protection device so as to decrease pad voltage overshoot when a fast transient electrical event occurs on the pad. Additionally, the holding voltage of the primary protection device is less than a holding voltage of the secondary protection device such that once the primary protection device has been activated the primary protection device clamps the pad voltage so as to minimize a flow of high current through the secondary protection device.

主权项

1. An apparatus comprising:
a first pad; an internal circuit electrically connected to the first pad; and a protection system configured to protect the internal circuit from transient electrical events, the protection system comprising:
a first primary protection device electrically connected to the first pad and configured to have a first holding voltage and to provide bi-directional blocking voltage protection; anda first secondary protection device electrically connected to the first pad and configured to have a second holding voltage and to provide bi-directional blocking voltage protection, wherein the first primary protection device has a current handling capability greater than a current handling capability of the first secondary protection device, and wherein the first secondary protection device is smaller than the first primary protection device and has a turn-on speed that is faster than a turn-on speed of the first primary protection device, and wherein a magnitude of the first holding voltage is less than a magnitude of the second holding voltage such that when the first primary protection device has been activated the activated first primary protection device clamps a voltage of the first pad and decreases a flow of current through the first secondary protection device.