Table of Contents
What is the use of reference voltage in ADC?
ADCs convert analog inputs that can vary from zero volts on up to a maximum voltage level that is called the reference voltage. The reference voltage determines the ceiling of what the ADC can convert, and is essentially the yardstick against which every proportion and result is measured.
What is meant by voltage reference?
A voltage reference is an electronic component or circuit that produces a constant DC (direct-current) output voltage regardless of variations in external conditions such as temperature, barometric pressure, humidity, current demand, or the passage of time.
What is reference voltage generator?
A voltage reference generator produces a constant voltage independent of the temperature and supply voltage [1]. Implementations of voltage reference generators, known as Bandgap Voltage Reference (BGR) Generators, usually, were designed to generate a constant voltage around 1.26 V at 27 °C (300 K).
Why do we use reference voltage?
Accurate measurements require a reference voltage that does not fluctuate with system conditions such as input voltage or ambient temperature. A voltage-reference IC provides a steady voltage that other ICs use to make measurements with the required accuracy.
What is ADC VREF?
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.
How the voltage reference affects ADC performance?
Unfortunately, the voltage-reference designs in this article can degrade ADC performance by adding unwanted tem- per ature drift and initial gain error. Higher-performance sys tems with 21+ bits may require a voltage-reference design that addresses these issues.
What is voltage reference Why is it needed?
A voltage reference is a precision device specifically designed to maintain a constant output voltage, even as parameters such as ambient temperature or supply voltage change. The precision of a voltage reference enables its use in several differ- ent types of applications beyond a data converter.
How is ADC calculated?
The ADC output is the ratio between the analog-signal voltage and the reference voltage. Any noise on the analog reference causes a change in the converted digital value. For example, with an analog reference of 3.3 V (VAREF = VDDA) and a 1 V signal input, the converted result is (1/3.3) × 4095 = 4D9h.
How do you calculate voltage from ADC?
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.
How is ADC voltage resolution calculated?
It is expressed as the number of bits output by the ADC. Therefore, an ADC which converts the analog signal to a 12-bit digital value has a resolution of 12 bits. -1. With a 3.3 V reference voltage, the resolution is 3.3/212 = 3.3/4096 = 0.805 (mV).
What is output of ADC?
An ADC carries out two processes, sampling and quantization. The ADC represents an analog signal, which has infinite resolution, as a digital code that has finite resolution. The ADC produces 2N digital values where N represents the number of binary output bits.
What is a voltage reference?
A voltage reference is simply that—a circuit or circuit element that provides a known potential for as long as the circuit requires it. This may be minutes, hours or years. If a product requires information about the world, such as battery voltage or current, power consumption, signal size or characteristics, or fault identification, then the
Why choose Linear Technology’s voltage references?
With a vast arsenal of voltage reference products, Linear Technology’s voltage references meet the needs of almost any application. See also Linear Technology’s application note AN82 “Understanding and Applying Voltage References,” available for download here.
What is the total uncertainty of the ltz1000’s reference voltage?
To give some perspective, in a laboratory instrument, the total uncertainty in the LTZ1000’s reference voltage due to noise and temperature would be only about 1.7ppm plus a fraction of 1ppm per month due to aging. While Zener diodes can be used to make very high performance references, they lack flexibility.
How do you design a voltage reference IC?
There are many ways to design a voltage reference IC. Each has specific advantages and disadvantages. The buried Zener type reference is a relatively simple design. A Zener (or avalanche) diode has a predictable reverse voltage that is fairly constant over temperature and very constant over time.