Depletion Mode Mosfets - Peak Electronics DCA75 User Manual

Atlas DCA Pro User Guide

Depletion Mode MOSFETs

The fairly rare Depletion Mode MOSFET is very similar to the
conventional Junction FET (JFET) except that the gate
terminal is insulated from the other two terminals. The input
resistance of these devices can typically be greater than
1000MΩ for negative and positive gate-source voltages.
Depletion Mode
characterised
voltage required to control the drain-
source current.
Modern Depletion Mode devices are
generally only available in N-Channel
varieties and will conduct some current
between its drain and source terminals even with a zero voltage applied across
the gate and the source. The device can only be turned completely off by taking
its gate significantly more negative than its source terminal, say –5V. It is this
characteristic that makes them so similar to conventional JFETs.
devices
by the gate-source
Depletion mode
MOSFET
are
N-Ch Depletion
mode MOSFET
Red-S Green-G Blue-D
Gate threshold
V GS ( on )=-2.918V
at I D =5.00mA
I DS
Enhancement mode
MOSFET
5.0mA
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April 2015 – Rev 1.4
V GS