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GriffinRU
RC-Monster Aluminum
 
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Join Date: Oct 2005
11.02.2007, 11:57 PM

Quote:
Originally Posted by sikeston34m View Post
Ok, according to the data sheets, here's the resistence values:

Big MOSFETS - RDS(ON)= 0.010 ohms max with 0.0082 ohms typical
No Gate Resistence value listed

Quark 80 amp MOSFETS - RDS(ON)= 2.2 megaohms
Gate Resistence = .6 ohms

The Big Mosfet data sheet doesn't list a Gate resistence value.

I wonder how much current the Gate lead circuit in the Quark 80 Brain board can support?
They should have Rg mentioned somewhere, maybe on the Graph...
This parameter responsible for FET's frequency response, noise and etc when you run simulation and important in design stage.
"Big" fets are usually slow, bulky and rated for high power plus in most cases have lower RDS(On) then "smaller" ones.

You need to check for fet driver part number in Quark 80 brain and study the circuit around it. To calculate required Voltage and Current check for switching frequency and total gate charge. Then do the same calc with different loads and temps.
   
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