According to the datasheet you must have more than 3-3.2V on the gate to
turn on the FET at reasonable Id current.
If everything is ok with pin directions, then check if you are able to
charge the 9.5nC on the gate during PWM ON period with your pullup resistor=
..


On Wed, Sep 16, 2015 at 7:51 AM, Brent Brown <brent.brown@clear.net.nz>
wrote:

> Are you getting contention when/if A4 and B3 connected together? i.e. wit=
h
> A4
> driving low and B3 driving low that might produce about a 2V high level.
>
> On 16 Sep 2015 at 16:26, IVP wrote:
>
> > Hi all,
> >
> > I'm trying to figure out what's up here.
> >
> > In the attached circuit, I'm driving a logic level FET with a 5V
> > 18LF1320
> >
> > The Standard PWM output (b3) wave drops to 2V when
> > connected to the 10R gate resistor. The FET doesn't turn
> > on
> >
> > The wave from the open-drain a4 + pull-up is 5V right to
> > the gate, the motor runs and is adjustable
> >
> > PWM frequency from b3 or a4 is  ~2kHz
> >
> > The datasheet says that each PIC pin (including presumably
> > b3) can source 25mA, yet the gate current through the 360R
> > is only 14mA.
> >
> > Any ideas ?
> >
> > TIA
> >
> > Joe
>
>
>
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