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Looking very good.
Thanks, Kiwi.
As you know, I was looking for a suitable P-channel Mosfet. I guess, I've found it - the tiny little FDN360P: http://www.distrelec.ch/Web/Downloads/_t/ds/fdn360p_eng_tds.pdf?mime=application/pdf
I also wanted to do some tests with SMD stuff.
So I decided to design a small "G5 Fan Tester" board.
The schematic with a totem pole driver:
The board from OHS Park ($4.25 for 3):
It's single sided and there is only a GND plane on the bottom.
After a bit of soldering:
The Mosfet is Q4. Note how tiny it is in comparison with the fan header!! The SMD soldering was done in accordance with this guide:
Size comparison with the G5 CPU fan:
Conclusion:
- SMD soldering is not as difficult as it looks
- The FDN360P stays very cool and appears to be the perfect solution for fans, which need to be switched on the P side.
- I've tested with 31.5kHz (with only a 100nF cap on the fan side) and with 123Hz (with an additional 47uF cap)
- the totem pole driver (which is used in this test setup) is not even necessary for low frequency PWM, so only an NPN transistor with a pullup is needed for driving the Mosfet.
MacTester
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