[Amps] MOSFET ratings

Ron Youvan ka4inm at tampabay.rr.com
Mon Jul 18 19:59:47 PDT 2011


Manfred Mornhinweg wrote:

> Steve,

>> One cross reference for the IXYS transistor you mention is
>> STP4NK80Z. If you look at the ST datasheet, it shows the lower
>> dV/dt as applying to the MOSFET diode

> Yes, that's right. But a MOSFET's internal diode is impossible to
> separate from the MOSFET. So if the diode is limited to 5 V/ns slew rate
> or so, then I can't see how the entire MOSFET could have a higher slew rate!

   If the diode is for protection, it doesn't effect the operation until the diode/s starts to 
conduct.  Therefor the device has speed limitations when it is over driven and different speed 
limitations when it is not over driven.
-- 
    Ron  KA4INM - Mistakes are often the stepping stones to utter failure.


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