Hello,
I'm currently working on a project that requires the use of an MCP475 DAC. Currently, it is being powered from the 3.3V source from on a Raspberry Pi and hence works in the range of 0V to 3.3V.
I need it to work in the range of 3.3V to +3.3V. By reading the spec sheets I found that I can use an OpAmp circuit to achieve this. I have some experience with electronics but, obviously, not enough. I have attached the circuit diagram and the equations needed to calculate the required resistances.
My understanding is that V_DD = +3.3V. And when V_out = +3.3V, V_o = +3.3V. And again, when V_out = 0, V_o =  3.3V. This gives you a pair of simultaneous equations which are then solved for the resistances. When I do the maths, I get the following:
R_2 = R_1
R_3 = 0
R_4 = R_4
So I thought maybe this means there is no R_3 and the values of R_2 and R_1 can be arbitrarily set as long as they're equal and then R_4 is also arbitrary. I build this circuit and nothing worked. What am I doing wrong? Please help me!
Thank you!
I'm currently working on a project that requires the use of an MCP475 DAC. Currently, it is being powered from the 3.3V source from on a Raspberry Pi and hence works in the range of 0V to 3.3V.
I need it to work in the range of 3.3V to +3.3V. By reading the spec sheets I found that I can use an OpAmp circuit to achieve this. I have some experience with electronics but, obviously, not enough. I have attached the circuit diagram and the equations needed to calculate the required resistances.
My understanding is that V_DD = +3.3V. And when V_out = +3.3V, V_o = +3.3V. And again, when V_out = 0, V_o =  3.3V. This gives you a pair of simultaneous equations which are then solved for the resistances. When I do the maths, I get the following:
R_2 = R_1
R_3 = 0
R_4 = R_4
So I thought maybe this means there is no R_3 and the values of R_2 and R_1 can be arbitrarily set as long as they're equal and then R_4 is also arbitrary. I build this circuit and nothing worked. What am I doing wrong? Please help me!
Thank you!
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