What is internal reference voltage?
A voltage reference is an electronic device that ideally produces a fixed (constant) voltage irrespective of the loading on the device, power supply variations, temperature changes, and the passage of time.
What is meant by VREF in ADC?
Vref, along with the number of bits of accuracy, is the voltage that defines how large the individual voltage steps are between unique digital inputs. ADC can work with the Vin between GND and Vref, or -Vref and +Vref or however the manufacturer decides to make their part.
Is the reference voltage External to the ADC?
The voltage reference is external to the ADC, and along with an amplifier to drive the reference, contributes to the overall system noise. For microcontrollers (MCUs) that have integrated (internal) ADCs, you may or may not have control over the reference 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.
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.
Can a MCU be used as a 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. This can cause inaccuracy, for example, if the MCU accepts 3.3 V analog inputs to the internal ADC while the V REF for that internal ADC is actually the supply voltage to the MCU or 5V.