I'm looking for some high-side pMOS switches to PWM-ize my Strobeshnik clock (currently the windings of the HDD motor are only switched by an ULN2803 at the low side, no PWM). All p-MOSFETS I seem to come about have humongous gate capacitance (500pF at best, most are 1500-3000pF), which makes them rather hard to drive. I tried to use an NPN transistor to drive the gate of one MOSFET of that kind and, as expected, it tends to close very slowly and overheat. Am I missing something here, or should I just look elsewhere? I tried searching in IRF and Fairchild databases.
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Joined: Sun. Jun 26, 2005
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Location: St.Petersburg, Russia