I need to keep a voltage level at .58VDC. I was trying to get away with doing it cheaply by using PWM but the problem is I need to use a capacitor to smooth out the voltage. It works but when I remove the PWM signal, the cap takes too long to discharge so getting an accurate reading isn't possible. I was going to try and use something like a resistor ladder network but the values I need are not common (581, 650, 825...).

I've never used a digital potentiometer but I guess they can't be so difficult. Then I thought about using an adjustable voltage regulator but I wasn't sure if it's right for my application. I have a thermistor where I need to keep the value at an exact voltage level (.58VDC). The current in the circuit is less than 10mA. Could I just tie the output and feedback of the voltage regulator directly to the output of the thermistor and push the easy button? Is there a software trick I could use to accomplish this?