Contents

**Introduction**

This tool computes the voltage resolution or the smallest voltage that can be measured by an analog-to-digital converter (ADC).

Every ADC is the number of bits it uses to digitize samples of the analog input. An **n** bit ADC produces **2 ^{n}** discrete digital levels.

The larger the number **n**, the higher the resolution.

Enter:

- Number of bits
- Maximum Analog Input Voltage
- Minimum Analog Output Voltage

**ADC Resolution Formula**

An ADC accepts an analog voltage at its input and converts it to an n-bit digital value. A 12-bit ADC for instance produces 2^{12} = 4096 discrete values at its output.

The analog resolution or the smallest value that can be measured by the ADC is given by the formula:

**(V _{max} – V_{min})/2^{n}**

where

**V**is the maximum input voltage_{max}**V**is the minimum input voltage_{min}**n**is the number of ADC bits

The difference between **V _{max}** and

**V**is the input voltage range

_{min}**Calculation Example**

A 12 bit ADC with an input voltage range of 3.3 Volt has a resolution of 0.81 mV.

Increasing the number of bits, increases the ADC resolution and therefore the precision of the measurement.

**ðŸ’¡**A related concept is the Quantization Error of the ADC.

**ADC Resolution Table**

The following shows the ADC resolution for an input voltage range of **5V**

Number of ADC Bits | ADC Resolution (Volt) |

1 | 2.5 |

2 | 1.25 |

3 | 0.625 |

4 | 0.3125 |

5 | 0.15625 |

6 | 0.078125 |

7 | 0.0390625 |

8 | 0.01953125 |

9 | 0.009765625 |

10 | 0.0048828125 |

11 | 0.00244140625 |

12 | 0.001220703125 |

13 | 0.0006103515625 |

14 | 0.00030517578125 |

15 | 0.000152587890625 |

16 | 0.0000762939453125 |

17 | 3.814697265625E-05 |

18 | 1.9073486328125E-05 |

19 | 9.5367431640625E-06 |

20 | 4.76837158203125E-06 |

21 | 2.38418579101562E-06 |

22 | 1.19209289550781E-06 |

23 | 5.96046447753906E-07 |

24 | 2.98023223876953E-07 |