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I plan on driving a heating coil of about 1.4 Ohms from a 3-4V power source; which gives an current draw of 2.14-2.85 A. So Watts from the following info is 6.42-11.4 W of power. The MCU will output a PWM signal at 490Hz at a voltage of 3-4V as well. knowing this I found a few potential mosfet's; and wanted some opinions from the pro's!

Here's the potential candidate list so far: SiA400EDJ SQA410EJ PSMN012-25YLC (this one is interesting as it has a unique package, but is due to be phased out..)

Any opinions or recommendations are appreciated! NOTE: I'm going for smallest size and smallest cost as well!

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  • \$\begingroup\$ Unfortunately, recommendations for specific parts are off-topic here. \$\endgroup\$
    – tcrosley
    Feb 19, 2015 at 5:33
  • \$\begingroup\$ Good source of information here electronics.stackexchange.com/questions/95252/…. Think the possibility to use a dedicate driver like TL427, even in this low frequency. \$\endgroup\$
    – GR Tech
    Feb 19, 2015 at 6:01

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Head over to your favourite parts supplier and enter "trench fet" into their search engine. I'm partial to Digikey but many other suppliers have similar search engines.

I think that you will find an awful lot of suitable MOSFETs to use. Choose one that has a threshold voltage down near 1V and then look at the datasheet to ensure that it is fully enhanced with your control voltage HI level.

FWIW - trench FETs are a class of MOSFET that has very low threshold voltage, very low Rds on, quite low max Vds voltage. Some are available in tiny packages with awesome current capability.

You should not need a heatsink if you choose the right FET.

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  • \$\begingroup\$ I've posted some trench FETs, why should the threshold college be near 1V? How would I check the data sheet to see if it's fully enhanced? \$\endgroup\$
    – Sam W
    Feb 19, 2015 at 6:23

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