Driving P-Channel Mosfet

[Simon]

Yes that will be fine.

[girishv]

Shrug, there's probably about as many logic-level as PMOS.

I suppose the widest option is regular NMOS + gate driver, a single (additional) component solution -- but a bit more expensive than a BJT or two.

Tim

I bought IRL6297SDPbF with V_DSS 20V / V_GS 12V± / R_DS 5.3mΩ at 2.5V.

https://www.infineon.com/dgdl/irl6297sdpbf.pdf?fileId=5546d462533600a40153565ff22f2575

These are logic level. The current rating is way higher than requirement.

[magic]

That's normal, the current rating is the maximum current it can conduct without burning, which doesn't mean anyone sane will want to actually operate it at the edge of burning.

It's just an impractical marketing number, like maximum power dissipation at 25°C case temperature

[Simon]

Yes I do tire of MOSFET datasheets, whatever the Rdson is double it unless you need really high power in which case trawl through the datasheet until you find the real value at high temperature and hope it's a mere 1.6x the 25C value given on the headlines.

Current capacity is more like peak without rupturing the thing but does not take thermals into consideration which you need o calculate. Power dissipation as far as I am concerned is a magic number they pull out of their asses as it has no basis in reality, You need to carefully work out the total thermal impedance and the temperature rise whilst being realistic about your local ambient in the enclosure.

[T3sl4co1l]

Yes I do tire of MOSFET datasheets, whatever the Rdson is double it unless you need really high power in which case trawl through the datasheet until you find the real value at high temperature and hope it's a mere 1.6x the 25C value given on the headlines.

An FYI about that: low voltage MOSFETs (<= 20V or so) have flatter Rds(on) vs. temp.  If given the choice between 20 and 30V devices, and the 20V has enough headroom to safely operate -- take it!

Tim

[Simon]

If only we could do that in automotive, reading the fine print of TVS diodes and with the only protection from a surge being to ride it out 50+V parts for 12V and 100+V parts for 24V

[girishv]

Yes I do tire of MOSFET datasheets, whatever the Rdson is double it unless you need really high power in which case trawl through the datasheet until you find the real value at high temperature and hope it's a mere 1.6x the 25C value given on the headlines.

The datasheet says R_DS(on) of IRL6297 @120^OC is 1.3x when I_D is 8.5A. The I_D of current design is between 0.65A and 1.0A.

[Simon]

with 1A I would not even worry.