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FET and capacitor in series question

lynch113

Jun 16, 2015
3
Joined
Jun 16, 2015
Messages
3
Hi there,
I will keep this simple, I am using a p channel FET to charge up a 0.33F ultra cap, there is a 1.3v drop diode in series with the capacitor. The FET is turned on and off once an hour to charge the empty cap to 3.7v. Will the current surge at turn on eventually ruin my FET? According to the datasheets, the FET can handle 20A surge, the diode 30A surge. Datasheet only provides capacitor ESR at 1kHz which is no good for me so I cannot calculate if too much current surges thru my FET at turn on. I don't have the space on my tiny smd pcb to add a large enough series resistor. I really appreciate any experience you could share with me on this! Thank you.
Capacitor is Vishay MAL219612334E3 : FET is Vishay SI2323DS-T1-E3
 

lynch113

Jun 16, 2015
3
Joined
Jun 16, 2015
Messages
3
It all depends on how much current your power supply can deliver
One last point, I suppose the little 1uF cap on the 5v regulator output does not have the potential to generate that kind of current even if for just an instant?
 
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