Electrostatic discharge protection device for mixed voltage interface

An integrated circuit device for electrostatic protection, comprising:

• a semiconductor substrate;
• a plurality of gates formed over the substrate;
• a first diffusion region of a first dopant type formed between two adjacent gates;
• and
• at least a second diffusion region of a second dopant type formed in the first diffusion region.

An integrated circuit for electrostatic discharge protection in a mixed voltage interface, comprising:

• a signal pad for receiving an electrostatic signal;
• a clamping device for providing electrostatic protection between a first voltage source and a second voltage source, the clamping device including
• at least two transistors connected in a cascode configuration,
• a first diffusion region of a first dopant type shared by two adjacent transistors, and
• a second diffusion region of a second dopant type formed in the first diffusion region;
• and
• a detection circuit responsive to the electrostatic signal for triggering the clamping device to direct the electrostatic signal to the second voltage source.

A method for protecting a mixed voltage interface from electrostatic discharge, comprising:

• providing a signal pad for receiving an electrostatic signal;
• providing a clamping device including
• at least two transistors connected in a cascode configuration,
• a first diffusion region of a first dopant type shared by two adjacent transistors, and
• a second diffusion region of a second dopant type formed in the first diffusion region;
• and
• providing a detection circuit responsive to the electrostatic signal for triggering a p-n junction between the first diffusion region and the second diffusion region of the clamping device.