what is Igss?

[Walter Harley]

I'm looking at the datasheet of a Supertex VN0106 MOSFET. It lists
"gate-body leakage (Igss)" of 100nA, at Vgs=+/-20v, Vds = 0v. This is a
mid-power N-channel enhancement MOSFET, in a TO92 case with source
internally connected to substrate.

What is gate-body leakage? Surely it can't be talking about leakage current
from the gate to source, on the order of 100nA?? That would equate to a
gate resistance of 20v/100nA = 200MEG or less, which while high is much less
than the trillions of ohms I thought MOSFET gates presented.

But if not that, then what?

Thanks,
-walter

 

[Uwe Bonnes]

Walter Harley <walterh@cafewalternospam.com> wrote:
: I'm looking at the datasheet of a Supertex VN0106 MOSFET. It lists
: "gate-body leakage (Igss)" of 100nA, at Vgs=+/-20v, Vds = 0v. This is a
: mid-power N-channel enhancement MOSFET, in a TO92 case with source
: internally connected to substrate.

: What is gate-body leakage? Surely it can't be talking about leakage current
: from the gate to source, on the order of 100nA?? That would equate to a
: gate resistance of 20v/100nA = 200MEG or less, which while high is much less
: than the trillions of ohms I thought MOSFET gates presented.

: But if not that, then what?

The gate may be high impedance. But the gate ESD protection is made with
bipolar junction parts. At high temperature, these junctions can get into
the range the data sheet mentions.

Bye

--
Uwe Bonnes bon@elektron.ikp.physik.tu-darmstadt.de

Institut fuer Kernphysik Schlossgartenstrasse 9 64289 Darmstadt
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