Patent ID: 8305718

Claim:
A low parasitic capacitance electrostatic discharge (ESD) protection circuit which is connected to an input/output (I/O) pad of a radio frequency (RF) core circuit, comprising: a first diode and a second diode, wherein the first diode is connected between a power source and the I/O pad, the second diode is connected between the I/O pad and the ground, and the first diode and the second diode are connected in series; a third diode and a fourth diode connected between the power source and the ground in series; and a fifth diode and a sixth diode connected between the I/O pad and the connection node of the third diode and the fourth diode reversely in parallel; wherein the first diode and the second diode have the same size of area, the third diode and the fourth diode have the same size of area, and the fifth diode and the sixth diode have the same size of area; and wherein the ratio of the area of the first diode, the third diode, and the fifth diode is 1:9:4.