Electrostatic discharge protection device

1. An electrostatic discharge protection device, comprising:

a double diffused drain N-type metal oxide semiconductor field effect transistor (MOSFET);

a P-type silicon controlled rectifier (SCR);

a double diffused drain P-type MOSFET; and

an N-type SCR,

wherein:

the double diffused drain N-type MOSFET is connected in parallel with the P-type SCR between an output pad and a first voltage pad;

the double diffused drain P-type MOSFET is connected in parallel with the N-type SCR between the output pad and a second voltage pad; and

the N-type SCR is connected in parallel with the P-type SCR between the first voltage pad and the second voltage pads,

wherein a P+ active region, connected to the first voltage pad, and a P-drift region configure the double diffused drain N-type MOSFET, and contact an HN-well and an HP-well simultaneously.

2. The electrostatic discharge protection device of claim 1 , wherein the P-type SCR includes a horizontal PNP bipolar junction transistor (BJT) mutually coupled with a vertical NPN BJT.

3. The electrostatic discharge protection device of claim 1 , wherein the N-type SCR includes a horizontal NPN BJT mutually coupled with a vertical PNP BJT.

4. The electrostatic discharge protection device of claim 1 , wherein an N+ active region, connected to the second voltage pad, and an N-drift region configure the double diffused drain P-type MOSFET, and contact an HN-well and an HP-well simultaneously.

5. The electrostatic discharge protection device of claim 1 , wherein an overlay margin of an N-drift region with respect to an N+ active region of the second voltage pad of the N-type SCR is smaller than an overlay margin of an N-drift region with respect to an N+ active region of the output pad of the P-type SCR.