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ocrdu
ocrdu
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To which ground should TVS or ESD diodes connect?

I am designing a circuit with both signal ground and earth. As far as I know, a TVS should be connected to the earth. However I have

What if there is a question, what if there is a huge voltage different between the ground and the earth?huge voltage different between the ground and the earth?

Let say I am protecting a 5-V V signal (respectwith respect to the ground) with a uni-directional TVS diode which is connected to the earth.

When ground = 0V0 V, earth = -1000V1000 V, signal = 5V5 V, in this case, the voltage difference between the signal and the earth is 1005V1005 V. Will the TVS diode be always conducting and pulling the signal pin very low?

When ground = 0V0 V, earth = 1000V1000 V, signal = 5V5 V and an 800-V V ESD event happened, the voltage across the TVS is still -200V200 V. Does that mean the TVS diode is never protecting the signal pin?

To which ground should TVS or ESD diodes connect

I am designing a circuit with both signal ground and earth. As far as I know, a TVS should be connected to the earth. However I have a question, what if there is a huge voltage different between the ground and the earth?

Let say I am protecting a 5-V signal (respect to the ground) with a uni-directional TVS diode which is connected to the earth.

When ground = 0V, earth = -1000V, signal = 5V, in this case, the voltage difference between the signal and the earth is 1005V. Will the TVS diode be always conducting and pulling the signal pin very low?

When ground = 0V, earth = 1000V, signal = 5V and an 800-V ESD event happened, the voltage across the TVS is still -200V. Does that mean the TVS diode is never protecting the signal pin?

To which ground should TVS or ESD diodes connect?

I am designing a circuit with both signal ground and earth. As far as I know, a TVS should be connected to the earth.

What if there is a huge voltage different between the ground and the earth?

Let say I am protecting a 5 V signal (with respect to the ground) with a uni-directional TVS diode which is connected to the earth.

When ground = 0 V, earth = -1000 V, signal = 5 V, in this case, the voltage difference between the signal and the earth is 1005 V. Will the TVS diode be always conducting and pulling the signal pin very low?

When ground = 0 V, earth = 1000 V, signal = 5 V and an 800 V ESD event happened, the voltage across the TVS is still -200 V. Does that mean the TVS diode is never protecting the signal pin?

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andykkkk
andykkkk
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To which ground should TVS or ESD diodes connect

I am designing a circuit with both signal ground and earth. As far as I know, a TVS should be connected to the earth. However I have a question, what if there is a huge voltage different between the ground and the earth?

Let say I am protecting a 5-V signal (respect to the ground) with a uni-directional TVS diode which is connected to the earth.

When ground = 0V, earth = -1000V, signal = 5V, in this case, the voltage difference between the signal and the earth is 1005V. Will the TVS diode be always conducting and pulling the signal pin very low?

When ground = 0V, earth = 1000V, signal = 5V and an 800-V ESD event happened, the voltage across the TVS is still -200V. Does that mean the TVS diode is never protecting the signal pin?