Patent ID: 7885046

Claim:
An electrostatic discharge (ESD) protection circuit comprising: a first diode and an SCR connected in series between an input node and a ground node, an anode of the first diode being connected to the input node, said first diode and SCR having a first capacitance and a first resistance; and a second diode connected between the input node and the ground node, an anode of the second diode being connected to the ground node, said second diode being formed at a junction between a highly doped region of a first conductivity type and a substrate of a second conductivity type, said second diode having a second capacitance, said first diode and SCR and said second diode having a total capacitance that is no more than what the total capacitance would be if the second diode were formed at a junction between a heavily doped region of a first conductivity type and a well region of a second conductivity type but the second capacitance is less than what it would be, the first capacitance is greater than what it would be, and the first resistance is less than what it would be if the second diode were formed at a junction between a heavily doped region of a first conductivity type and a well region of a second conductivity type.