paralleling irf640N to operate 12v ignition coil

[nxt_]

Dear All,
Greetings, i intend to operate a load 12v,upto 4A (Ignition coil), with two irf640n in parallel. so kindly what i need is to know what is the limitations of paralleling Mosfets (irf640). also how to calculate the Series gate resistor for both irfs together, any additional information will be appreciated.

Many Thanks For Your Time and patience.

Thanks

 

[erikl]

IRF640N is good for a typ. drain current of 13A (@ 100°C), so why would you want to spend two of them in parallel for 4A ?

Generally a series gate resistor should be small enough to load the gate (input) capacitance as fast as (or just a bit faster than) you need the drain current to rise to its required max. value.