Patent ID: 9673189
Date: 2017-06-06
CPC Classifications: H01L

Claim:
1. An electrostatic discharge (ESD) unit, comprising: a first device; and a second device coupled to the first device in parallel; and a trigger element coupled to the first device in series, wherein in an ESD event, the trigger element is turned on by an electrostatic voltage, and the first device is turned on by the turned-on trigger element before the second device is turned on, and wherein the first device comprises, as a first NPN BJT, a parasitic NPN BJT in a GGMOS, or a non-parasitic NPN BJT, the second device comprises a silicon-controlled rectifier (SCR) that comprises a second NPN BJT and a PNP BJT, a base of the first NPN BJT is electrically connected to a terminal of the trigger element, a collector of the PNP BJT, and a base of the second NPN BJT, an emitter of the first NPN BJT is grounded, a collector of the first NPN BJT is electrically connected to an emitter of the PNP BJT and an I/O pad, an emitter of the second NPN BJT is grounded, and a collector of the second NPN BJT is electrically connected to a base of the PNP BJT.