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I am attempting to create a 0-5V analog output signal. No need to drive a load. I desire to control this via a 3.3 digital MCU.
I have attempted to translate the 3.3v PWM to 5v via a n channel mosfet and then through a single or double RC low pass filter.
This there a more accurate or better way to do this besides using a separate IC to do so?
simulate this circuit – Schematic created using CircuitLab
You could replace the MOSFET with a single CMOS logic converter - this will drive the filtering circuit and be somewhat more accurate because it has a push pull output and can work up to much higher frequencies than an open-drain MOSFET and 1 kohm resistor. Use a single-element logic device to keep board usage small. I'm sure TI have a device that fits the bill - look for TTL to CMOS inverter or buffer.
R3 participates in charging the capacitors but it doesn't participate in its discharge. To obtain the average value accurately, the rations R1/R3 and R2/R3 should be as high as possible. Try 100k and 10n.
Depending on what you connect at the output, some kind of buffer could be necessary (load stage may charge or discharge the capacitors and affect the average value you detect).
