What is the smallest change in input voltage that the ADC can detect?

What is the smallest change in input voltage that the ADC can detect?

The ADC resolution is the smallest distinguishable change in input (e.g., 3.3V/4095, which is about 0.81 mV). The resolution is the change in input that causes the digital output to change by 1. Figure 14.4. A 12-bit ADC converts 0 to 3.3V on its input into a digital number from 0 to 4095.

What is the smallest change in voltage?

1 Answer

• ADC range which is the maximum and minimum ADC input. For this problem the range is 3.2V, -3.2V.
• ADC resolution which is the smallest distinguishable change in input. For a 12 bit converter this would be 6.4V/4096 = 0.0015625V.

How to calculate ADC output voltage?

ADC has a resolution of one part in 4,096, where 212 = 4,096. Thus, a 12-bit ADC with a maximum input of 10 VDC can resolve the measurement into 10 VDC/4096 = 0.00244 VDC = 2.44 mV. Similarly, for the same 0 to 10 VDC range, a 16-bit ADC resolution is 10/216 = 10/65,536 = 0.153 mV.

What is the smallest change in the input signal that can be detected by an instrument called?

Resolution
Resolution is the smallest measurable input change. It denotes the smallest change in the measured variable to which the instrument responds.

Which type of ADC is faster?

flash ADC
The flash ADC is the fastest type available. A flash ADC uses comparators, one per voltage step, and a string of resistors. A 4-bit ADC will have 16 comparators, an 8-bit ADC will have 256 comparators.

How to choose reference voltage for an ADC-power electronic?

The value produced by a 10-bit ADC with a 5V reference and a 3.3V analog input signal (where 3.3V is the highest value measured at the input) would be: (V IN x 1,024) /V REF = (3.3 V x 1,024)/5 V = 675.84 However, the result, if V REF were 3.3 V, rather than 5 V, would be: (V IN x 1,024) /V REF = (3.3 V x 1,024)/3.3 V= 1,024

How is the resolution of an ADC determined?

The resolution of an ADC is defined by dividing V REF by the total number of possible conversion values. (Think of the resolution of the ADC as equivalent to the smallest step size of the ADC.)

Can a microcontroller use a reference voltage?

For microcontrollers (MCUs) that have integrated (internal) ADCs, you may or may not have control over the reference voltage. Some MCUs have an external pin that allows you to provide a voltage reference of your choosing, but others will simply use the MCU’s supply voltage.

What should the V ref be for an ADC?

The V REF for your ADC should be very stable regardless of the temperature it experiences. It should demonstrate excellent performance over temperature. In short, the lower the number of ppm/°C, the better. Additionally, the initial output voltage accuracy of VREF should be low, in the range of 0.5% or less for precision ADC applications.