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Cut-off current through an N-channel power MOSFET with negatively charged gate

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htg

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How low can such current be?
 

Hi,

Maybe low microamperes, maybe in the nanoamperes region.
It depends on a lot of parameters ... and mainly on the part you use.
I expect a 100mA rated MOSFET to have less current than a big 250A MOSFET.

Why do you ask? What's the application, problem or idea?

Klaus
 

How low it "can" be is immaterial, how high it might be is
more relevant to circuit design if you're not hand-picking
parts for that quality.

GIDL (gate induced drain leakage) is a thing in some types
of MOSFETs (though I've seen it more in integrated, plain
FETs). That means after some distance into negative Vgs,
drain current increases from its minimum.
 

How low it "can" be is immaterial, how high it might be is
more relevant to circuit design if you're not hand-picking
parts for that quality.

GIDL (gate induced drain leakage) is a thing in some types
of MOSFETs (though I've seen it more in integrated, plain
FETs). That means after some distance into negative Vgs,
drain current increases from its minimum.

I am clearly asking about MOSFETs, so gate current should be much smaller than drain current.
 

I am clearly asking about MOSFETs, so gate current should be much smaller than drain current.
Gate curreent is always very low and independent of drain voltage, since the gate looks like a capacitor.

What is the perceived problem you have?
 

Gate curreent is always very low and independent of drain voltage, since the gate looks like a capacitor.

What is the perceived problem you have?

In the response of dick freebird above there is the statement:

"GIDL (gate induced drain leakage) is a thing in some types
of MOSFETs (though I've seen it more in integrated, plain
FETs). That means after some distance into negative Vgs,
drain current increases from its minimum."

My original question is: what is the drain current in an N-channel MOSFET with maximally negatively charged gate?
Lets assume we are dealing with a power MOSFET, Idmax=100 A.
 

I am clearly asking about MOSFETs, so gate current should be much smaller than drain current.

Sure, if you were clear, but you were not. Just what is
"cutoff current" supposed to mean to the average person
schooled in the art? Drain current, unless you say otherwise.
You didn't until this #4 post.

Short of breakdown there will be some gate leakage which
the manufacturer only specifies a one-sided (max) limit
for, and quite often only for the "on" condition Vgs(max)
(expecting the user to not overdrive the gate, as this can
pose other problems as well).

There's no answer for MOSFETs generically. Gate oxide
thickness, quality, area and the effects of field control
structures (i.e. how much field the oxide sees, under
operating conditions) all matter. And all of them are device-
design as well as wafer-shot specific.

If you had -a- device in mind the datasheet would give
you some guidance about the corners of the "box".

And for the power MOSFETs which incorporate a gate
protection diode, which are some, all of this goes out
the window.

Now in post #6 you're back to drain current which is what
I told you about originally. Which is certainly dependent on
drain voltage and temperature. All of which you'd look to the
specific product datasheet, to say - not ask people to make
up an untethered guess.
 

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