An analog-to-digital converter (ADC, or A/D) is an electronic circuit that converts an analog voltage into its digital representation. The latter is an integer that is proportional (relative to an internal or external reference voltage) to the magnitude of the sampled analog voltage While an analog signal has (theoretically) infinitely fine resolution, a digital signal can resolve only down to the voltage increment represented by its LSB.
How to select the Analog to Digital Converter ?
Selecting the Analog to Digital Converter would require the tradeoff between various parameters such as resolution, channel count, power consumption, size, conversion time, static performance, dynamic performance and price. Below table gives a high level comparison of commonly used ADC’s.
ADC Type | Pros | CONS | MAX Resolution | MAX Sample rate | Applications |
|---|---|---|---|---|---|
Successive Approximation (SAR) | Good Speed/ Resolution Ratio | No inheritant anti-aliasing protection | 18 bits | 10 MHz | Data loggers, Temperature sensors, Bridge Sensors, General purpose, CMOS imaging |
Delta Sigma | High Dynamic performance, Inheritant anti-aliasing protection | Hysteresis on unnatural signals | 32 bits | 1 MHz | Data Acquisition, Noise and Vibration, Audio, Precision Industrial Measurements |
Dual Slope | Accurate, Inexpensive | Low speed | 20 bits | 100 Hz | Voltmeters, Multimeters |
Pipelined | Very Fast | Limited Resolution | 16 bits | 1 GHz | Oscilloscopes, wireless and line communications, Test and Measurement, Instrumentation, Medical Imaging, RADAR systems |
Flash | Fastest | Low bit resolution, High Power Consumption | 12 bits | 10 GHz | Oscilloscopes, Microwave measurements, fiber optics, RADAR detection, Wideband Radio |
