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What is an Analog-to-Digital Converter?

Analog-to-Digital Converters (ADCs) are widely used for bringing an analog signal into the digital world, where it can be efficiently processed and manipulated in embedded applications. An ADC simply converts a voltage level to a digital value. ADCs can be found as standalone IC’s, or they can be integrated into a microcontroller (MCU) as an on-chip ADC.

Why use an on-chip ADC?

The vast majority of microcontrollers in Microchip’s product portfolio feature on-chip ADCs. By using these integrated ADCs, designers can save the cost of using a separate ADC, and have a smaller footprint on their board layout since you’re not adding a separate component. Additionally, on-chip ADCs have the following benefits when compared to their standalone counterparts:

Reduced Development Time – In addition to eliminating board layout issues, on-chip ADCs are easy to use and can be configured with just a few lines of code. This allows you to reduce your development time of both software and hardware.

Increased System Flexibility - Since the integrated ADC has direct connections to the Central Processing Unit (CPU) and other integrated modules, you have more options for configuring the ADC to interact directly with other resources on your microcontroller. The integrated ADCs in 8-bit PIC® and AVR® microcontrollers can operate at 5V, which gives both a wider range and a better Signal-to-Noise Ratio (SNR) of your ADC readings than other integrated ADCs that run at 3.3V.

Lower Power Consumption – In PIC and AVR MCUs, the CPU can be put into SLEEP mode, while the integrated ADC continues to operate using its dedicated clock source. Because the ADC can wake the CPU when necessary, you can lower the overall power consumption of your system.

Choose the right ADC for your design

When choosing an ADC for your design, selecting a converter with the highest possible resolution result is always preferable; however, in many ADCs (both on-chip and standalone), high resolution carries a penalty in conversion speed. Therefore, attention must be paid to the tradeoffs involved during the selection process. Microchip’s 8-bit MCUs offer a wide range of converters with various speeds and resolutions, enabling designers to build their application with the proper balance of analog capabilities.