Basically I am trying to make a 2-bit DAC that can interface to an external device via one signal wire. I want to create a 3-step signal that can be ~0V, 2.5V, and ~5V.
For starters, I tried using two NPN transistors controlled by two 3.3V output pins from an MCU.
Here is the schematic I have simulated in LT Spice...
With this schematic, I can get my ~0V and ~2.5V fine, but I cannot get 5V. When I apply voltage only to Q5 (the top NPN), I only get 3.03V at the output.
Looking this up with google only yield results for a "tri-state buffer" that has the output possibilities of 0V, 5V, and high-z. I cannot find a shcematic or IC to accomplish what I am looking for exactly....but maybe my search terms are incorrect?
I need a suggested schematic mod or an IC to accomplish what I am looking for if anyone has any suggestions! Thanks!
I found this Fig. in another post which will take care of reaching up to the 5V. I just need to add a second transistor switch and create a voltage divider which I already know how to do. The LED will replaced by an outbound signal.