Re: LM393 driving small MOSFET



ian field wrote:

My problem is "how fast can an LM393 drive the gate of a small MOSFET"? At
the moment the exact type of MOSFET isn't finalised, and even if it was I've
yet to see a data*** give a straight answer on the actual value of gate
capacitance,

Really ?


if I knew that I could calculate the charge/discharge time with
the minimum allowable 393 O/P pull up resistor.

Indeed.


One thing that would ease the problem, is if it is possible to wire the pair
of comparators in parallel to increase the O/P sink capability, the
alternative is to drive an external transistor to get more current - but the
whole point of using the 393 was to eliminate a quantity of discrete
transistors.

You might be better off with an op-amp then.

Graham

.