ADC Bit Resolution Calculator

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 2n 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 212 = 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:

(Vmax – Vmin)/2n

where

  • Vmax is the maximum input voltage
  • Vmin is the minimum input voltage
  • n is the number of ADC bits

The difference between Vmax and Vmin is the input voltage range

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.

💡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 BitsADC Resolution (Volt)
12.5
21.25
30.625
40.3125
50.15625
60.078125
70.0390625
80.01953125
90.009765625
100.0048828125
110.00244140625
120.001220703125
130.0006103515625
140.00030517578125
150.000152587890625
160.0000762939453125
173.814697265625E-05
181.9073486328125E-05
199.5367431640625E-06
204.76837158203125E-06
212.38418579101562E-06
221.19209289550781E-06
235.96046447753906E-07
242.98023223876953E-07

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