TVS Diode Create Offset voltage

Thread Starter

PettaPraveen

Joined May 2, 2019
3
Hi,

I am using TVS diode for Camera output lines. RG Signal gets offset of 5V When I connected a Uni-Directional TVS Diode ( MSP3V3-M3/89A ) in it.

The RG Signal is about 0 to 3.8V. When removed the TVS diode there is no offset in the Signal.

Thanks
 

TeeKay6

Joined Apr 20, 2019
531
Hi,

I am using TVS diode for Camera output lines. RG Signal gets offset of 5V When I connected a Uni-Directional TVS Diode ( MSP3V3-M3/89A ) in it.

The RG Signal is about 0 to 3.8V. When removed the TVS diode there is no offset in the Signal.

Thanks
Are you placing the TVS device in series with the RG signal or between the RG signal and some other wire/signal/ground? The proper connection is NOT in series but between two different wires/signals/signal-and-ground. Bear in mind that a uni-directional TVS is just a diode with a controlled breakdown voltage (not much different than a zener diode); as any other diode, it will easily conduct current in its forward direction with only a small voltage drop (< 1V).
 
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Thread Starter

PettaPraveen

Joined May 2, 2019
3
What's the voltage rating of the TVS diode?

Is it a bidirectional type (what's the part number)?
Thanks,

Unidirectional diode Part number is MSP3V3-M3/89A

Voltage - Reverse Standoff (Typ)3.3V
Voltage - Breakdown (Min)4.1V
Voltage - Clamping (Max) @ Ipp11.5V

The RG Signal is about 0 to 3.8V. When removed the TVS diode there is no offset in the Signal but the same TVS is used in H1 and H2 here it works fine. There is no offset for H1 and H2. I am getting only for RG
 
Last edited:

Thread Starter

PettaPraveen

Joined May 2, 2019
3
Are you placing the TVS device in series with the RG signal or between the RG signal and some other wire/signal/ground? The proper connection is NOT in series but between two different wires/signals/signal-and-ground. Bear in mind that a uni-directional TVS is just a diode with a controlled breakdown voltage (not much different than a zener diode); as any other diode, it will easily conduct current in its forward direction with only a small voltage drop (< 1V).
Thanks, Teekay6
No, I am Placing TVS Diode in Parallel with the RG and ground. The RG Signal is about 0 to 3.8V. When removed the TVS diode there is no offset in the Signal but the same TVS is used in H1 and H2 here it works fine. There is no offset for H1 and H2. I am getting only for RG
 

TeeKay6

Joined Apr 20, 2019
531
Thanks, Teekay6
No, I am Placing TVS Diode in Parallel with the RG and ground. The RG Signal is about 0 to 3.8V. When removed the TVS diode there is no offset in the Signal but the same TVS is used in H1 and H2 here it works fine. There is no offset for H1 and H2. I am getting only for RG
Would it make sense to replace (for testing only) the TVS with a simple diode (e.g. 1N4148) to see if the offset persists?
 
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