“All analog-to-digital converters (ADC) and digital-to-analog converters (DAC) need to have a reference voltage (usually a voltage). This reference voltage source is a necessary module in the ADC and DAC system. Some converters require an internal reference, while others require an external reference. Knowing this, then we need to consider how to choose the appropriate ADC or DAC reference type in the application?
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Q: Reference type of ADC and DAC
All analog-to-digital converters (ADC) and digital-to-analog converters (DAC) need to have a reference voltage (usually a voltage). This reference voltage source is a necessary module in the ADC and DAC system. Some converters require an internal reference, while others require an external reference. Knowing this, then we need to consider, how to choose the appropriate ADC or DAC reference type in the application?
Generally speaking, there are 3 main types of benchmarks to choose from: internal, external, and power.
1. Internal benchmarks
Some reference voltages built into the converter. In the typical circuit below, the internal reference type helps to reduce the number of components used in the circuit design, thereby simplifying design issues. But this is easily affected by the ambient temperature. Because temperature changes will cause the reference voltage to shift and affect the stability of the converter.
2. External benchmarks
The external reference uses the applied voltage (or current) as the reference signal of the converter, as shown in the following typical circuit. It can make the design more flexible.
For example, in high-resolution ADC applications, engineers can use low noise and positive/negative references (+/- Vref) (if required) to enable the system to achieve noise-free code resolution. It is also possible to increase the temperature compensation of the system to improve the stability of the reference. Of course, the increase in the number of components and design complexity caused by the use of external benchmarks and their associated costs are also issues that need to be considered.
3. Power
The advantage of using the power supply as a reference is that any power supply noise can be directly coupled to the power supply. This is equivalent to isolating the device from any power supply noise.
Q: Reference type of ADC and DAC
All analog-to-digital converters (ADC) and digital-to-analog converters (DAC) need to have a reference voltage (usually a voltage). This reference voltage source is a necessary module in the ADC and DAC system. Some converters require an internal reference, while others require an external reference. Knowing this, then we need to consider, how to choose the appropriate ADC or DAC reference type in the application?
Generally speaking, there are 3 main types of benchmarks to choose from: internal, external, and power.
1. Internal benchmarks
Some reference voltages built into the converter. In the typical circuit below, the internal reference type helps to reduce the number of components used in the circuit design, thereby simplifying design issues. But this is easily affected by the ambient temperature. Because temperature changes will cause the reference voltage to shift and affect the stability of the converter.
2. External benchmarks
The external reference uses the applied voltage (or current) as the reference signal of the converter, as shown in the following typical circuit. It can make the design more flexible.
For example, in high-resolution ADC applications, engineers can use low noise and positive/negative references (+/- Vref) (if required) to enable the system to achieve noise-free code resolution. It is also possible to increase the temperature compensation of the system to improve the stability of the benchmark. Of course, the increase in the number of components and design complexity caused by the use of external benchmarks and their associated costs are also issues that need to be considered.
3. Power
The advantage of using a power supply as a reference is that any power supply noise can be directly coupled to the power supply. This is equivalent to isolating the device from any power supply noise.
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