1. ESD protection circuit

2. Circuit 1

3. DM model 1.) the circuit shows that the SRV05-4 is short to shut down,when the surge is DM model, so the circuit can protect the IC away from DM model surge(EFT,lightnin g).

4. CM model 1.) the ESD and CDE are the CM model, so the SRV05-4 will do not work because it is not connect to GND thinking of HI- POT. 2. the protection for CM model relies on the transformer. But the isolation of transformer is 1500V, so it is not enough for ESD AND CDE

5. Circuit 2

6. DM model 1.) the circuit shows that the SRV05-4 is short to GND, when the surge is DM model, so the circuit can protect the IC away from DM model surge.

7. CM model 1.) the ESD and CDE are the CM model, so the SRV05-4 will do work because it is connected to GND. 2. The transformer also supply the 1500V isolation

8. Discrete design IC RJ45 ICM When ESD occurs, the blue wire will bring out inductance and it will result V B =L B * di/dt. 2.) the red wire will bring out inductance and it also result V R =L R * di/dt caused by ESD and V B higher than ESD only 3.) the V IC = V C + V R may be is higher than the IC ESD degree.

9. Integrated design IC RJ45 with ESD device ICM When ESD occur, the V IC = V C is less than the IC ESD degree.

10. conclusion 1.Thinking of HI-POT, DM model and CM model, the ESD device is best between the transformer and PHY side in our RJ45 ICM product. 2.the integrated design is better than the discrete design 3.the design method is same to 1000base type.