Parrallel PWM outputs

Hi,

New to Arduino so forgive if this is obvious, but, can I add multiple PWM outputs together feeding into a low pass filter to give a little extra power to a 0 to 5V pseudo analogue output ? I need around 45mA max?

So far no answers, is this a really stupid question or nobody actually knows the answer ?

The PWM subsystems on the chip allow all sorts of coordinated actions between two related pins. You might be able to configure it to synchronise two pins but I would not trust it. Read the datasheet.

You should use a proper MOSFET or opamp to amplify the output signal (from one pin) to the level you need.

How are you going to change the settings for both pins simultaneously so they don't ever
fight each other? I don't know a way.

You need to low-pass filter then amplify the signal if you want significant analog power.
A high-current rail-to-rail opamp or buffer might be what you need to buffer the output
of the filter.

Filter circuits should never be randomly loaded, the load impedance affects the filter response
directly - another reason to buffer the output, as well as allowing more reasonable component
values (smaller capacitors)