ESD PROTECTION CIRCUIT WITH ISOLATED DIODE ELEMENT AND METHOD THEREOF

摘要

An ESD protection circuit (20) includes an ESD device (24) and an isolation diode element (30). The ESD device includes a drain-source junction isolated ESD transistor (26,28). The isolation diode element is coupled in series with the ESD device and configured for providing ESD protection to a transistor device (22) needing ESD protection. Responsive to -Vgs conditions on a gate of the protected transistor device, the series coupled isolation diode element prevents a forward biasing of the drain-source junction of the ESD transistor prior to a breakdown condition of the isolation diode element. In addition, responsive to an ESD event sufficient to cause damage to the protected transistor device, the series coupled isolation diode element permits an occurrence of the breakdown condition. Furthermore, the ESD protection circuit can operate in both (i) a polarity of normal operation of the protected device and (ii) an opposite polarity other than in normal operation of the protected device.