High voltage, high frequency esd protection circuit for rf ics

Abstract

Improved ESD protection circuits for RFICs requiring both high voltage and high frequency operation is described. A cascode grounded gate snap-back NFET (GGNFET) combined with a precharge circuit and a diode network results in a positive ESD protection clamp with low capacitance and high turn-on voltage. The positive ESD protection clamp provides ESD protection to an IC during a positive voltage ESD pulse. Exemplary embodiments of a negative ESD protection clamp are disclosed where a bias circuit or a charge pump is used in place of the precharge circuit in a manner that allows the combination of the bias circuit or the charge pump together with a diode network and a cascode grounded gate snap-back NFET to provide protection against negative ESD voltage pulses. The combination of a positive and a negative ESD protection clamp provides ESD protection to an IC during either a positive or a negative voltage ESD pulse. Alternate embodiments further reduce the capacitance of the ESD protection circuit by using only a positive ESD clamp to provide ESD protection during a positive ESD pulse while protection for a negative ESD pulse is provided by a discharge path formed by a path of an RF front-end switch coupled to a negative ESD diode.