Question:
Using Ohm's law and the formula for resistors in parallel, what is the output voltage of the R-2R DAC when inputs D7 and D6 are connected to each combination of ground and 3.3 volts? Please present the results as a table.
Answer:
The general formula for the R-2R ladder DAC circuit presented in the activity can be expressed as:
Where Vref = 3.3V and D7 – D0 can be either 0V or 3.3V.
In our particular situation, we only consider D7 and D6, therefore the equation becomes:
The output voltages for each combination of 0V and 3.3V for D7 and D6 becomes:
|
D7 |
D6 |
Vout |
|
0V |
0V |
-3.3V |
|
0 |
3.3V |
-1.65V |
|
3.3V |
0V |
0V |
|
3.3V |
3.3V |
1.65V |