list modern good mosfets - Page 1
Forum section: electronics / beginners

author: SArepairman
author_rank: Frequent Contributor
timestamp: October 12, 2013, 05:50:07 pm
content: So I noticed that alot of people have trouble with mosfets because they are using 1940s technology. (as free electron wrote in the hate of mosfets thread)I would like to make a list of well behaved mosfets that we can use with little hassle in various applications.if I was to do a digikey order of good general purpose mosfets to have around what would i get?stuff thats not the 2n7000

author: M. András
author_rank: Super Contributor
timestamp: October 12, 2013, 06:01:55 pm
content: look at the nxp's lfpak packages those arent old and most of them logic level around 1.9v threshold

author: AndyC_772
author_rank: Super Contributor
timestamp: October 12, 2013, 06:16:38 pm
content: Quote from: SArepairman on October 12, 2013, 05:50:07 pmThe wrong MOSFETs for your project, probably. I rarely use the same one twice, there's always a different trade-off between size, voltage rating, RDSon and gate capacitance.It would help to have an idea of what you have in mind as the application. Switched mode power supply? Motor control? Power on/off switching? What voltage range and switching frequency? SMT or through hole?

author: SArepairman
author_rank: Frequent Contributor
timestamp: October 12, 2013, 07:12:54 pm
content: Quote from: AndyC_772 on October 12, 2013, 06:16:38 pmI have no project in mind I guess i just thought it would be a good thread idea

author: mrflibble
author_rank: Super Contributor
timestamp: October 12, 2013, 07:18:55 pm
content: Quote from: AndyC_772 on October 12, 2013, 06:16:38 pmHow about motor control, 50 V, 10 A, 22 kHz switching. Any candidates that spring to mind?

author: AndyC_772
author_rank: Super Contributor
timestamp: October 12, 2013, 08:09:14 pm
content: It's not really my area, so no specific part numbers, sorry.For 50V use I'd be looking at one with at least 100V VDS rating, to have a chance of coping with inductive turn-off spikes. I'll assume the board layout keeps these down to a minimum and that any spikes are suppressed by TVS diodes or similar if necessary. If not, consider improving the layout and suppression first, but if that's not an option, a 200V transistor might be a better bet. It'll have higher gate capacitance and/or higher RDSon, though.22kHz is quite slow, so you could go for a device with higher than average gate capacitance in order to achieve lower RDSon. Conduction losses are I^2R, so if I = 10A, I^2 is 100, so that's 1W per 10mOhms resistance.As a first guess, I might look at this one:http://www.vishay.com/docs/71141/SUP85N10.pdf100V rating, 12mOhm RDSon @ VGS=4.5V, continuous drain current rating 60A. It has a high capacitance, but since it's being switched quite slowly that shouldn't be the end of the world. Provided the device driving it is up to the job, it should do nicely with a small heat sink.

author: Neilm
author_rank: Super Contributor
timestamp: October 12, 2013, 10:08:57 pm
content: The only time I have re-used FETs is when I worked for a company that assembled their own PCBs. They did small runs of the designs so keeping the number of different MOSFETs down kept the inventory down and the bean counter happy

author: chickenHeadKnob
author_rank: Super Contributor
timestamp: October 12, 2013, 10:21:24 pm
content: Quote from: mrflibble on October 12, 2013, 07:18:55 pmI don't often switch motors at 50V, 10A but when I do I use:IRFB3077's- make sure you get the real ones.Actually keep these in stock for general purpose under 60V high current use.

author: RSTPhysics
author_rank: Newbie
timestamp: October 12, 2013, 10:41:14 pm
content: I've used FQP50N06 a little for some LED-projects, was what the supplier I bought them from had that was fairly low Vgs(th).

author: mrflibble
author_rank: Super Contributor
timestamp: October 13, 2013, 02:26:40 pm
content: Quote from: chickenHeadKnob on October 12, 2013, 10:21:24 pmThat Rds_on is pretty damn low. Gate charge is definitely on the high side, but no surprise there. Shouldn't be too much of a problem at 22 kHz. Nice one, thanks!