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What is the use of VREF in ADC?
Voltage references (VREF) are beneficial and often necessary for high-accuracy signal chain applications. This is because a standard signal chain contains a data converter, such as the Analog-to-digital converter (ADC) or Digital-to-analog converter (DAC), which measure or create a precise signal.
What is the step size of 8bit ADC if VREF is 1.28 V?
If we need a step size of 10 mV for an 8-bit ADC, then Vref = 2.56 V, because 2.56 V / 256 = 10 mV….V. ref.
| Vref (V) | Vin Range (V) | Step Size (mV) |
|---|---|---|
| 1.28 | 0 to 1.28 | 1.28 / 1024 = 1.25 |
| 1.024 | 0 to 1.024 | 1.024 / 1024 = 1 |
| Note: Vref Relation to Vin Range for an 10-bit ADC |
What does vrefa have to do with ADC?
VREFA has nothing to do with VREF, it is just another reference for the ADC. The INTERNAL option is even more interesting. It uses the internal reference voltage of the chip, Vref, but again has nothing to do with ADC0.Vref, unless this INTERNAL option is selected.
Is the voltage reference Vref the same as ADC0?
The INTERNAL option is even more interesting. It uses the internal reference voltage of the chip, Vref, but again has nothing to do with ADC0.Vref, unless this INTERNAL option is selected. The Voltage Reference VREF is explained in chapter 18 where you see that it has 5 different settings:
How is the reference device related 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. Figure 1: Both the voltage reference device and the amplifier (reference buffer) can contribute to overall system noise for the ADC. (Source: e2e.ti.com)
Why do you need a voltage reference for Vref?
Any insight is appreciated. The voltage reference provides an accurate and stable point for the ADC and DAC for their conversions. A voltage reference can be picked with different levels of voltage accuracy and temperature stability.