{"product_id":"adafruit-mcp3421-18-bit-adc-stemma-qt-qwiic","title":"Adafruit MCP3421 18-Bit ADC - STEMMA QT \/ Qwiic","description":"\u003cp\u003eThe Adafruit MCP3421 18-bit ADC is a simple, inexpensive, and easy-to-use 18-bit, 240 SPS, single-channel ADC with an I2C interface that can run up to 3.4MHz clock rate. A perfect component whenever you need an ADC that has differential inputs, adjustable gain, and a built-in precision\/low-drift reference voltage.\u003c\/p\u003e\n\u003cp\u003eOne of the trade-offs with getting 18-bit precision is that the ADC is not going to be very fast: you can configure the chip to do a faster 12-bit conversion at 240 SPS, but at 18-bits it slows down to 3.5 SPS.\u003cbr\u003eThat's because the way a \u003ca href=\"https:\/\/en.wikipedia.org\/wiki\/Delta-sigma_modulation\"\u003esigma-delta ADC\u003c\/a\u003e works, it 'guesses' the analogue voltage and uses a comparator to determine whether the input is higher or lower. Each 'guess' takes an extra step, and thus\u003cbr\u003ehalves the throughput, so 12-bit is 240 SPS, and 14-bit is 1\/4 (2-bit) slower, 60 SPS. Ditto 16-bit is 1\/4 slower, 15 SPS, and finally, 18-bit is 3.75 SPS.\u003c\/p\u003e\n\u003cp\u003eThe MCP3421 is already set up for differential inputs, which means that you can read positive or negative differences between the two inputs, as long as both signals are between 0 and 2.048V. This means it's not going to be great for reading stuff like potentiometers, where you have a single-end reading referenced to ground, and you want to read the full range from 0 to Vcc. It is great, however, for reading sensors like strain gauges, pressure sensors, or thermocouples.\u003c\/p\u003e\n\u003cp\u003eWe have a ready-to-go \u003ca href=\"https:\/\/github.com\/adafruit\/Adafruit_MCP3421\"\u003eArduino library\u003c\/a\u003e that makes usage simple: select the sample rate\/precision you want and one-shot or continuous mode. Then read values over I2C! This sensor has a fixed address, so you may want to use a \u003ca href=\"https:\/\/learn.adafruit.com\/adafruit-tca9548a-1-to-8-i2c-multiplexer-breakout\"\u003emultiplexor\u003c\/a\u003e if you want to connect multiple MCP3421s on a single I2C bus.\u003c\/p\u003e\n\u003cp\u003eTo 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 \u003ca href=\"\/search?q=sparkfun+qwiic\u0026amp;narrow_by=\u0026amp;sort_by=relevency\u0026amp;page=1\"\u003eSparkFun Qwiic\u003c\/a\u003e 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.\u003c\/p\u003e\n\u003cp\u003eQT Cable is \u003cstrong\u003enot\u003c\/strong\u003e included, but we have a variety in the \u003ca href=\"\/search?q=stemma+qt\u0026amp;narrow_by=\u0026amp;sort_by=relevency\u0026amp;page=1\"\u003eshop\u003c\/a\u003e.\u003c\/p\u003e\n\u003cp\u003eComes with a bit of 0.1\" standard header in case you want to use it with a \u003ca href=\"\/collections\/solderless-breadboards\"\u003ebreadboard\u003c\/a\u003e or \u003ca href=\"\/collections\/prototyping-pcbs-and-perfboard\"\u003eperfboard\u003c\/a\u003e. Four mounting holes for easy attachment.\u003c\/p\u003e\n\u003cp\u003e\u003ciframe width=\"560\" height=\"315\" src=\"\/\/www.youtube.com\/embed\/UqqeaS5QIZ4?si=YgBmorLTU1pIaiIC\u0026amp;start=160\" title=\"YouTube video player\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" allowfullscreen=\"allowfullscreen\"\u003e\u003c\/iframe\u003e\u003c\/p\u003e\n\u003ch2\u003eSpecifications\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e18-bit ΔΣ ADC\u003c\/li\u003e\n\u003cli\u003eDifferential Input Operation\u003c\/li\u003e\n\u003cli\u003eSelf Calibration of Internal Offset and Gain Per Conversion\u003c\/li\u003e\n\u003cli\u003eOn-Board Voltage Reference:\n\u003cul\u003e\n\u003cli\u003eAccuracy: 2.048V ± 0.05%\u003c\/li\u003e\n\u003cli\u003eDrift: 15 ppm\/°C\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003eOn-Board Programmable Gain Amplifier (PGA):\n\u003cul\u003e\n\u003cli\u003eGains of 1,2, 4 or 8\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003eOn-Board Oscillator\u003c\/li\u003e\n\u003cli\u003eINL: 10 ppm of FSR (FSR = 4.096V\/PGA)\u003c\/li\u003e\n\u003cli\u003eProgrammable Data Rate Options:\n\u003cul\u003e\n\u003cli\u003e3.75 SPS (18 bits)\u003c\/li\u003e\n\u003cli\u003e15 SPS (16 bits)\u003c\/li\u003e\n\u003cli\u003e60 SPS (14 bits)\u003c\/li\u003e\n\u003cli\u003e240 SPS (12 bits)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003eOne-Shot or Continuous Conversion Options\u003c\/li\u003e\n\u003cli\u003eProduct Dimensions: 25.4mm x 17.8mm x 12.3mm\u003c\/li\u003e\n\u003cli\u003eProduct Weight: 3.0g\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eResources\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\u003ca href=\"https:\/\/learn.adafruit.com\/adafruit-mcp3421-18-bit-adc\"\u003ePrimary Guide\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Adafruit","offers":[{"title":"Default Title","offer_id":50847486476561,"sku":"ADA5870","price":5.7,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0901\/6285\/6209\/files\/adafruit-mcp3421-18-bit-adc-stemma-qt-qwiic-the-pi-hut-ada5870-41706632413379.jpg?v=1735213980","url":"https:\/\/abcd3032.myshopify.com\/products\/adafruit-mcp3421-18-bit-adc-stemma-qt-qwiic","provider":"Tayyab Zak","version":"1.0","type":"link"}