Power supply spike tolerance limit

Hello everybody. I am putting a Jetson into a car. To protect it from spikes, I am using a TVS diode. Right now it’s a 1.5KE18A. It should arrest any voltage spikes at ignition or otherwise. It should even protect against a lightning strike.

However… is it enough?

Standoff voltage: 15.3V
Breakdown voltage: 17.1V
Clamping voltage: 18.9V

The question is therefore, would a Jetson survive a spike from 12-13V to 17-18V? As the maximum input voltage is 19V, it should, but this is a spike, not a continuous supply.

The specs you wrote sound ok but you should double check the 1.5KE18A. From what I can find, its clamping voltage is 25.2V, exceeding the 20V max VDD_IN for Jetson Orin Nano and NX.

Be sure that your carrier board leaves the MODULE_ID pin open for the higher voltage range.

Thank you. According to a friend, a 18V spike is impossible in a car, unless it’s one without any electronics. Such a spike, if unaddressed, would fry the car’s own systems, so it is actally arrested by design. Fluctuations are therefore possible, but never beyond 14-15V.

However, I heard some people saying that their car killed their Jetson. A mystery indeed. Yes, perhaps that TVS diode isn’t a bad idea after all. Thanks for the tip about the MODULE_ID!

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