I also thought of this, but I think in this case the failure mode would be open circuit. The datasheet does not specify minimum switch current nor contact plating material.
Some Hamlin reed tube data sheets stated the contact material, but not the moulded ones.
-- Mikko OH2HVJ
Unfortunately our power budget for this part is way less than a uA. We could use a hall with 10ms on / 500ms off cycle, but currently we're not waking up that often.
-- mikko
The peak current is over 5A measured by adding a short piece of wire for P6042 probe. That might add some inductance and the probe BW is only 50MHz, so the peak might be a bit higher.
We have a PCB revision scheduled for August and that one will definetely include the series resistor. In the meanwhile I'm thinking if there'd be any problems going to a large 10nF or medium 1nF cap.
About caps. Where else do you this kind of ranges. The same PCB may have
0.4 pF for RF matching and 3.3F for power supply. Thats 1:10000000000000!-- mikko
What a disgusting mental image. Series resistor it is.
Thank you everybody for comments, this was again SED at its' best. I'll report back when we have experience of about 10k units with series resistor.
-- mikko
I don't fully understand your layout as you describe it, "||" ? this tells me you put the cap and r in parallel ?
The snubber circuit needs to be a series circuit across the contact points. In your case a ceramic cap only across the contact terminals should do.
Jamie
...
Yes, the R and C are parallel for EMC filtering and debouncing. The high current path closes through the power supply planes and bypass caps.
-- mikko
Yes shock can do it. I have a LED flashlight that is water proof to about
30 feet. The concept is good. It uses a read switch and a moveable magnet to turn it on. So no possible leakage path . But it fell off the night s tand and then would not work. I got it working, but have no faith in it as a rugged flashlight.Dan
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