Teensy 4.1 External PTC Fuse

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airpanther

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Good day,

Any recommendation for selecting an appropriate external PTC fuse to protect Vin on a Teensy 4.1 (to protect from external voltage regulator spikes)? If the 3.3V max current is 250ma and the processor uses up to 100ma, do I still need an Itrip of 350? The other issue, is a PTC with an Itrip of 350 likely has an Ihold that is quite a bit less... limiting the available current to run normally.

Any suggestions? In addition to a TVS diode, is this an effective solution to inrush current?

Thanks!
Robert
 
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Might be good to explain about the problem you're trying to protect.

You said "external voltage regulator spikes", which seems strange as usually voltage regulators aim to give consistent voltage output, without spikes.

But in general for voltage spikes, a TVS diode is usually the way to protect. A resistor or PTC fuse (really just a resistor) before the diode limits the current which can flow into the diode, helping it to do the protection. But a fuse alone doesn't protect against voltage at all.

This is why explaining the problem better would allow us to give better advice about which parts to use.
 
Hi Paul, thank you for your reply. I should have posted this as part of a previous thread I had on the topic. But once I posted this one, I couldn't delete it. I'll post my latest question on the proper thread, thanks!
 
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