US 9,425,186 B2Granted

Electrostatic discharge protection circuit

AssigneeMicrochip Technology Incorporated

InventorChe-Hong Chen

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Abstract

The present invention discloses an electrostatic discharge protection circuit, comprising a diode and a N-type metal-oxide-semiconductor (NMOS) transistor. The diode locating on a N-well comprises an high P-doping concentration region and an nonadjacent high N-doping concentration region. The NMOS transistor, locating on a P-well, comprises a drain, a source and a gate, and the drain and the source are formed by the high N-doping concentration region. Wherein the P-well further comprises a high P-doping concentration region near the source, the drain of the NMOS is electrically connected to the high N-doping concentration region of the diode, the source of the NMOS and the adjacent high P-doping concentration region are electrically connected to a ground, the gate of the NMOS transistor electrically connected to a trigger point. Accordingly, the electrostatic discharge protection circuit has a low parasitic capacitance, wide operating voltage range and high electrostatic discharge (ESD) capability for resolving the problems about the ESD of the RX pins.

Claims14

Dependent claims

An electrostatic discharge protection circuit, formed by a diode and a metal-oxide-semiconductor (MOS) transistor set on a semiconducting substrate, comprising:

a first well, having a first conducting mode;
a second well, locating adjacent to the first well and having a second conducting mode;
a first high doping concentration region, locating in the second well and having a second conducting mode, the first high doping concentration region electrically connected to a connected pad;
a second high doping concentration region, locating in the second well and having a first predetermined distance from the first high doping concentration region, having a first conducting mode;
a third high doping concentration region, locating in the second well and having a first conducting mode;
a fourth high doping concentration region, locating in the first well and having a second predetermined distance from the third high doping concentration region, having a first conducting mode, the fourth high doping concentration region electrically connected to a ground pad;
a fifth high doping concentration region, locating in the first well and locating adjacent to the fourth high doping concentration region, having a second conducting mode, the fifth high doping concentration region electrically connected to the ground pad;
and an electrode, locating on a surface of the second well between the third high doping concentration region and the fourth high doping concentration region, the electrode electrically connected to a trigger point;
wherein the second high doping concentration region is electrically connected to the third high doping concentration region.

6 more elements

Dependencies are inferred from the claim text.