The Adafruit MCP3421 18-Bit ADC is an affordable and user-friendly 18-bit, 240 SPS, single-channel ADC with a fast I2C interface capable of handling a clock rate of up to 3.4MHz. It is an ideal selection for any application requiring an ADC with differential inputs, customizable gain, and a precise low-drift reference voltage built-in.
While the Adafruit MCP3421 18-Bit ADC offers precise measurements, it sacrifices speed due to the sigma-delta conversion process. At 18-bits, the ADC has a slower speed of 3.5 SPS compared to the faster 12-bit conversion option at 240 SPS. This is because the ADC has to make extra 'guesses' and use a comparator, reducing the throughput by half. For example, 14-bit is 1/4 (2-bit) slower at 60 SPS, 16-bit is 15 SPS, and 18-bit is the slowest at 3.75 SPS.
The MCP3421 is optimized for differential inputs, allowing for accurate readings of both positive and negative differences between two signals, as long as they fall within the range of 0 to 2.048V. However, it may not be suitable for single-end readings with a reference to ground, such as potentiometers, where the full range of 0 to Vcc is desired. It excels in reading data from sensors like strain gauges, pressure sensors, and thermocouples.
Our product includes an Arduino library that allows for easy usage. Simply choose your desired sample rate and precision, along with one-shot or continuous mode, and read values over I2C. This sensor has a static address, so a multiplexer may be necessary if you wish to connect multiple MCP3421 devices to a single I2C bus.
To get you going fast, we spun up a custom-made PCB in the STEMMA QT form factor, making it easy to interface with. The STEMMA QT connectors on either side are compatible with the SparkFun Qwiic I2C connectors. This allows you to make solderless connections between your development board and the MCP or to chain it with a wide range of other sensors and accessories using a compatible cable.
QT Cable is not included, but we have a variety in the shop.
Comes with a bit of 0.1" standard header in case you want to use it with a breadboard or perfboard. Four mounting holes for easy attachment.
Technical Details
- 18-bit ΔΣ ADC
- Differential Input Operation
- Self Calibration of Internal Offset and Gain Per Each Conversion
- On-Board Voltage Reference:
- Accuracy: 2.048V ± 0.05%
- Drift: 15 ppm/°C
- On-Board Programmable Gain Amplifier (PGA):
- Gains of 1,2, 4 or 8
- On-Board Oscillator
- INL: 10 ppm of FSR (FSR = 4.096V/PGA)
- Programmable Data Rate Options:
- 3.75 SPS (18 bits)
- 15 SPS (16 bits)
- 60 SPS (14 bits)
- 240 SPS (12 bits)
- One-Shot or Continuous Conversion Options
Product Dimensions: 25.4mm x 17.8mm x 12.3mm / 1.0" x 0.7" x 0.5"
Product Weight: 3.0g / 0.1oz
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