# DAC max output voltage

**URL:** <https://forum.arduino.cc/t/dac-max-output-voltage/1150561>\
**Category:** UNO R4 WiFi\
**Created:** [July 22, 2023, 7:03am UTC](https://forum.arduino.cc/t/dac-max-output-voltage/1150561 "2023-07-22T07:03:04Z")\
**Posts on this page:** 8\
**Page:** 1

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**Author:** ![fab64](https://avatars.discourse-cdn.com/v4/letter/f/85e7bf/32.png) [@fab64](https://forum.arduino.cc/u/fab64)\
**Post date:** [July 22, 2023, 7:03am UTC](https://forum.arduino.cc/t/dac-max-output-voltage/1150561/1 "2023-07-22T07:03:04Z")

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I would like to use the DAC for its basic purpose: getting a CC voltage.

I have configured the DAC to 8-bit resolution.

Setting the DAC's value to 255 I get an output voltage of ~2.76/2.77 V (5V = ~4.85V).

Is the DAC using an internal reference instead of the 5V? Can I change it? Which is the DAC's max output voltage and current?

Thx

```arduino
int value = 0;  

void setup() {
  Serial.begin(115200);
  analogWriteResolution(8);
  analogWrite(DAC, value);
}

void loop() {
  if (Serial.available() > 0) {
    value = Serial.parseInt();

    Serial.println("DAC Value " + String(value));
    analogWrite(DAC, value);
  }
  delay(500);
}

```

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<div class="post-metadata">

**Author:** ![b707](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/b707/32/854321_2.png) [@b707](https://forum.arduino.cc/u/b707)\
**Post date:** [July 22, 2023, 7:04am UTC](https://forum.arduino.cc/t/dac-max-output-voltage/1150561/2 "2023-07-22T07:04:24Z")

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Please change the title - ADC and DAC is not the same....

ADC doesn't have "output voltage"

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<div class="post-metadata">

**Author:** ![fab64](https://avatars.discourse-cdn.com/v4/letter/f/85e7bf/32.png) [@fab64](https://forum.arduino.cc/u/fab64)\
**Post date:** [July 22, 2023, 7:48am UTC](https://forum.arduino.cc/t/dac-max-output-voltage/1150561/3 "2023-07-22T07:48:49Z")

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Thank you for reporting the typo. I am aware of the difference between ADC and DAC.

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**Author:** ![johnerrington](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/johnerrington/32/340106_2.png) [@johnerrington](https://forum.arduino.cc/u/johnerrington)\
**Post date:** [July 22, 2023, 8:10am UTC](https://forum.arduino.cc/t/dac-max-output-voltage/1150561/4 "2023-07-22T08:10:10Z")

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See the datasheet  
[https://www.renesas.com/eu/en/document/dst/renesas-ra4m1-group-datasheet?r=1054146](https://www.renesas.com/eu/en/document/dst/renesas-ra4m1-group-datasheet?r=1054146)

 ![image](https://europe1.discourse-cdn.com/arduino/original/4X/5/e/3/5e34d7b74a9508b82b89ed3396af2e6b0c0c2a68.png)

you may need to refer to the hardware datasheet - chapter 36  
[https://www.renesas.com/eu/en/document/mah/renesas-ra4m1-group-users-manual-hardware?r=1054146](https://www.renesas.com/eu/en/document/mah/renesas-ra4m1-group-users-manual-hardware?r=1054146)

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<div class="post-metadata">

**Author:** ![jim-p](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/jim-p/32/922840_2.png) [@jim-p](https://forum.arduino.cc/u/jim-p)\
**Post date:** [July 22, 2023, 8:16am UTC](https://forum.arduino.cc/t/dac-max-output-voltage/1150561/5 "2023-07-22T08:16:29Z")

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Do you know what the reference voltage is?

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<div class="post-metadata">

**Author:** ![JohnLincoln](https://avatars.discourse-cdn.com/v4/letter/j/7ba0ec/32.png) [@JohnLincoln](https://forum.arduino.cc/u/JohnLincoln)\
**Post date:** [July 22, 2023, 9:05am UTC](https://forum.arduino.cc/t/dac-max-output-voltage/1150561/6 "2023-07-22T09:05:12Z")

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fab64,

Using your sketch, I get a value of 4.66V.  
For me the "5V" is 4.68V.

 ![Screenshot 2023-07-22 095700](https://europe1.discourse-cdn.com/arduino/original/4X/6/f/e/6fee6c573cb4eccb7b28fd469ea66a6c30cb6bc9.png)

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<div class="post-metadata">

**Author:** ![fab64](https://avatars.discourse-cdn.com/v4/letter/f/85e7bf/32.png) [@fab64](https://forum.arduino.cc/u/fab64)\
**Post date:** [July 22, 2023, 2:16pm UTC](https://forum.arduino.cc/t/dac-max-output-voltage/1150561/7 "2023-07-22T14:16:23Z")

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Hi John,

You are right. I have tried again and I now get the right values (4.79V @5V=4.81V).

In my previous test, I connected a LED to the DAC output trough a too low resistor (330 ohm, instead of 10k) by mistake. I hardly see the colors so I use marked boxes to keep resistors and clearly that resistor was in the wrong box.

Thx

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<div class="post-metadata">

**Author:** ![johnerrington](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/johnerrington/32/340106_2.png) [@johnerrington](https://forum.arduino.cc/u/johnerrington)\
**Post date:** [July 23, 2023, 7:34am UTC](https://forum.arduino.cc/t/dac-max-output-voltage/1150561/8 "2023-07-23T07:34:49Z")

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I'm color blind (red green) so I always check the value with a dmm.

You didnt mention you had something already conected to the DAC output!