Vds max for the IRF610 is 200v, vs 100v for the IRF510.
So yes, the IRF610 can survive a higher voltage power supply
However Rds-on (resistance from drain to source with transistor fully turned on)
goes up from 0.54 ohms on the IRF510 to 1.5 ohms on the IRF610.
So the IRF610 may not be a complete win. ?
The devices have exactly the same thermal characteristics, so at DC the IRF510
could handle 3x the current that the IRF610 can. ?Power dissipation is all in Rds-on for DC.
At RF we spend significant time in the transition region, so not obvious just how much Rds-on
will affect performance.?
Mouser prices the IRF610 about 25% cheaper than the IRF510, so cost is not an issue.
Well worth trying.
The output transformer at T7 in the Bitx40v3 is currently a 1 to 4 impedance transformer,
the windings may need to be adjusted to give the FET a higher impedance load when?
running with higher supply voltages. ?Caps for the low pass filter should be rated
for several hundred volts as power levels increase.
Jerry, KE7ER
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On Wed, Nov 15, 2017 at 08:47 pm, John Backo wrote:
The IRF510 has a typical drain voltage rating of 70v. That is why the DC voltage maximum
is typically 48v. This allows a signal excursion of about 96v with only an occasional peak
of 96v. There is some distortion but it is hardly noticeable.
The typical drain voltage of the IRF610 is about 100v. Hence one can use a little higher
DC and signal voltage. Probably about 20% or so. That means about 30-40% more power
output. Even at 48v, the power output would be a it cleaner.
