Hi daniel
The Freedom K20 has a MK20DX128VLH5 device on LQFP64, unfortunately this device only has the 6-bit DAC key, that only can route to the internal comparator input, it does not have the option to put it to an external pin.
Others K20 like the K20_100 MHz has this option with the 12-bit Digital-to-Analog Converter (DAC), but not the K20_50 MHz.
Regarding to do it with the PWM,I believe that is not a good option, you only can control the pulse width, but not the voltage, so you will have a signal that if you measure you can get the 10mV ( average of the DC voltage) but the true is that you will have a signal with a little time on high and long time on low, I do not know what is your application, but probably this kind of signal are not properly for your application and also this signal can get electrical noise.
Regards
Vicente Gomez
