P Mosfet suggestion

Hello! I would like to use p mosfet in a low power arduino. The battery will be 3 - 4.7V so the gate will be the in this range. The source will be also the same, 3 - 4.7V, as long as it will come from the same battery. What smd p mosfet do you recommend with fully switch off for my low power project? The device i will use is 0.5 - 1 Ampere. Now i use the IRLML6401 but i get 250uA current flow from source when Gate is HIGH. Thank you

What is the load? What current would you consider allowable when the device is off? Are you driving the gate to the same voltage as the source to switch off, or some other voltage?

athtest: Now i use the IRLML6401 but i get 250uA current flow from source when Gate is HIGH.

Are you sure. Datasheet states Idss of 1uA at room temp. Are you using a gate/source resistor? Post the diagram. Leo..

Here is the diagram. The arduino works in 3 - 4.7V without regulator. https://www.dropbox.com/s/arwd637iptuxnd7/p-mosfet.jpg?dl=0

When arduino OUTPUT LOW, and END Device connected i have 250uA Current flow. When i disconnect END DEVICE it drops to 0.20uA as i designed it.

What do you suggest? Did i damaged the mosfet? I see on datasheet that VDS = VGS, ID= -250μA . That means that if gate and source voltage are the same (in my project they are) i have 250uA flow? Or is it 1uA as Wawa said? Sorry, but i do not understand very well mosfet specifications.

VDS = VGS, ID= -250μA is at 0.55volt. The threshold voltage.

A 10k pull-up resistor consumes 100uA/volt when the output pin is low.

Try a 100k pull-up resistor. Leo.

Hi, Can I suggest you download ExpressPCB CAD program, it is free, easy to downoad and is not encombered with lots of other apps to load with it.


You can make your own component too.

When you want to show a file use REPLY rather than QUICK REPLY, it has an attachment facility, so you can post your files as an attachment.

Your diagram does not identify gate, drain and source and end device.

A standard type circuit diagram helps immensly, or hand draw using standard circuit symbols and post a picture of it.

Tom..... :) When the gate is HIGH, what is the Gate to Source voltage?