p-channel mosfet heat dissipation

GaryW2

Joined Apr 28, 2019
2
Hello crookedspoon & Audioguru
Just to be clear, running the spice model for the IFR4905 in the DC analysis mode, returns the following result:
For a drain current of 1.47 Amps the gate to drain voltage needs to be -3.92 volts, of course this isn't set in stone, and will varies from device to device and temperature.
I’ve included the circuit for clarity.

1639081639105.png
Regards GaryW.
 

cormih

Joined Mar 26, 2017
2
Where did you get that odd idea?
There's no such thing as a "linear one".
All MOSFETs can (and are) used as DC switches.
If you look at fig.8 from the data sheet you would notice that the curves stop for signal of 1 (one) pulse 10ms wide. There are no curves for dc signal. Also Rds on is defined ONLY for pulses of 300us and duty cycle of less than 2% (note 4) which is far away than a dc signal. Search linear MOS, an N-type, from IXYS, for example IXTK90N25L2. which is specifically built for working in dc signals.
 
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