ESD protection circuit for mixed-voltage I/O ports using substrated triggering

摘要

An ESD protection circuit for mixed-voltage input/output (I/O) circuits. The ESD protection circuit utilizes substrate triggering of a parasitic NPN BJT under a cascaded NMOS transistor pair with a current generated by a triggering current generator. The ESD protection circuit is triggered much faster. Under normal circuit operations, the triggering current generator can also endure high-voltage signals without overstressing internal components and retains good reliability.