sparkfun Qwiic 12-Bit ADC Hook-Up Manual page 6

In addition, there is an onboard 10kΩ potentiometer, attached to AIN that is used in the examples and can be
used for testing. The potentiometer is connected directly to 3.3V and GND so the voltage range will always be
defined by the power input to the board.
For the potentiometer, we recommend using 1.5mm flathead precision screwdriver. Click to enlarge.
When using AIN as the negative/reference input be sure to cut the jumper to remove the potentiometer for
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accurate differential readings (see Jumper section below).
ADS1015 ADC
The ADS1015 ADC is a low-power 12-bit analog-to-digital converter (ADC), which includes a built-in integrated
voltage reference and oscillator. At the core of its operation, the ADC uses a switched-capactior input stage and a
delta-sigma (ΔΣ) modulator to determine the differential between AIN (positive analog input) and AIN (negative
analog input). Once the conversion is completed, the digital output is accessible over the I C bus from the internal
conversion register.
Interested in how ΔΣ ADCs work? Here are TI's application notes: How delta-sigma ADCs work, Part 1 and
Part 2.
Annotated image of potentiometer on board.
Click to enlarge.
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