Vgs nmos turn on voltage

let's say I have this nmos

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it says the Vgs,th is between 2V-4V

I believe the higher drive voltage will reduce my Rds,on.... so.... do I just want to drive this as high as makes sense for my circuit? this fet has a Vgs max of 30V.... and a Vgs,th of 2V-4V... how do you figure what to drive it at? I would just do 10V and move on but I'm wondering what a more thoughtful approach might be

thanks

Reply to
panfilero
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From Figure 1, VGS > ~5.5V has very little improvement in Rds_on

How serious are your needs for low Rds_on? ...Jim Thompson

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| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
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Reply to
Jim Thompson

=A0 =A0 ...Jim Thompson

=A0 =A0| =A0 =A0mens =A0 =A0 |

=A0 | =A0 =A0 et =A0 =A0 =A0|

=A0|

=A0 =A0 =A0 |

not very serious more just trying to understand does it matter how high I go with my Vgs? 12V better than 9V ? that kinda thing

Reply to
panfilero

[snip]

Depends on your definition of "better" ;-)

Minimal improvement in Rds_on. More gate swing, if done at a high rate equals more drive power consumed. ...Jim Thompson

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| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
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Reply to
Jim Thompson

Those are the range of what to expect from lot to lot and condition of operations. If you're using this as a switch, I'd be well above the MAX Vgs(Thr) voltage to turn it on. Also, gate charge and your driving device has a lot to do with it so to not hover to long over the threshold point, otherwise, this can cause heating of the FET due to it being in the linear region for too long.

That part there is best used in a 5v or more logic switch signal, I don't think it would be a good idea to use that in a 3.3V logic level system, unless of course, you plan on using a gate driver with a charge pump in it.

Jamie

Reply to
Jamie

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From the data sheet's "On Characteristics", Vgs(th) - the gate
threshold voltage - is defined as that voltage which, when applied
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Reply to
John Fields

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