DAC output voltage level - STM32F410RB(NUCLEO)

[AMS12345]

Hi @mƎALLEm ,

I referred the application notes to increase analog amplitude, but whatever the digital amplitude configured i am able to get only 1.85v as analog volt. How to get 3.3v as volt level for output for DAC.

[waclawek.jan]

DAC output is very high impedance, and even with buffer on, it's still relatively high impedance. So you have to buffer it before applying any significant load.

JW

PS. Please don't @-invoke individual users with no particular reason.

[AMS12345]

Hi @waclawek.jan 

 

As per your suggestion, i used buffer but its not working. Also, i checked the DAC output voltage in different controller(means had same 2 stm32f410rb nucleo board) for the same code and input i get different voltage level in output of these boards. for board no.1 i got 1.85v and for another board i got 0.04v, but i configured for 3.3.v as output voltage level. Also using opamp lm386 only i able to hear the output audio with noise.

 

Thanks in advance for your assistance.

[waclawek.jan]

If two different boards running the same code output different waveforms, they are very likely damaged, maybe both of them.

Maybe you should start with a simple code outputting discrete levels. Also, observe the output using oscilloscope and check the output waveform to expectations or post.

Note, that DAC outputs are NOT 5-volt tolerant. And, as I've said, they are of high impedance and are relatively easy to damage by connecting excessive loads or external voltage sources, or through ESD.

Make sure that there is nothing else on the board connected to these pins, see the Nucleo's schematics/manual.

Also note, that DAC outputs are proportional to reference voltage on VREF+ pin. I don't know how VREF+ is connected on those boards.

JW