Patent ID: 8199447

Claim:
A semiconductor device having an electrostatic discharge (ESD) protection circuit comprising an integrated circuit, the integrated circuit including: a plurality of reverse-biased steering diodes connected in series between a rail and a substrate of the integrated circuit, wherein the plurality of reverse-biased steering diodes includes two diodes connected to one another at an input port that receives an input signal; a bypass Zener diode connected between the rail and the substrate wherein the bypass Zener diode is reverse-biased and provides a high impedance path between the rail and the substrate when the input signal has a first polarity relative to a signal ground and a magnitude that is less than a first predetermined voltage level, and the bypass Zener diode is in breakdown and provides a low impedance path between the rail and the substrate when the input signal has the first polarity and a magnitude that exceeds the first predetermined voltage level; and a substrate Zener diode connected between the signal ground and the substrate wherein the substrate Zener diode is forward-biased when the bypass Zener diode is in breakdown, the substrate Zener diode is reverse-biased and provides a high impedance path between the signal ground and the substrate when the input signal has a second polarity relative to the signal ground and a magnitude that is less than a second predetermined voltage level, and the substrate Zener diode is in breakdown and provides a low impedance path between the signal ground and the substrate when the input signal has the second polarity and a magnitude that exceeds the second predetermined level; wherein the second polarity is opposite the first polarity and the ESD protection circuit provides ESD protection to one or more devices connected to the input signal.