So, my summarizing question really is - to drive general purpose N channel MOSFETs, do I need a 'standard' low side driver?
I am using the SMD D Pak so want to keep heat to a minimum.
The AVR output pins are pretty robust and are active sinking and sourcing so many pwm switching applications using 'logic level' n-channel mosfets in a low side switching configuration don't require external driver help at all, just drive the gate directly with the arduino output pin. But again it's all about your specific device, applications, and how much load power you are trying to switch.
I thought so too - however, narrowing down parts using the following parameters it seems most FETs have this sort of value, or those with smaller are in the smaller SOT223 packages that will get hot anyway.N channel.10-20A cont55-75ATypical threshold 3VRds test max 5V
EDIT: I've just widened up my search options a bit, with larger currents - and I've come up with this device. Much lower on resistance :-) all the super low resistance devices appear to be in all the weird and wonderful packages, most of which I've never heard of.http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATASHEET/CD00002155.pdf
A logic-level MOSFET has a higher total gate charge and so requires more switching power than standard drive. High power means high-current, and low voltage means higher current still (peak current drive requirements are in excess of 1 amp for popular logic-level power MOSFET's and may be as high as 10 amps). A standard drive MOSFET reduces current requirements two-fold in comparison to logic-level drive.
instead of using a logic level FET one can use a 'normal' level FET and connect the power supply of the driver to the 12V supply, this way - the driver forces high peak current 12V signals into the gate of the FET? Correct?