Si7021-A20 2 I C HUMIDITY AND TEMPERATURE SENSOR Features Precision Relative Humidity Sensor Factory-calibrated 2 3% RH (max), 080% RH I C Interface High Accuracy Temperature Sensor Integrated on-chip heater 0.4 C (max), 10 to 85 C 3x3 mm DFN Package 0 to 100% RH operating range Excellent long term stability Up to 40 to +125 C operating Optional factory-installed cover range Low-profile Wide operating voltage Protection during reflow (1.9 to 3.6 V) Excludes liquids and particulates Low Power Consumption Ordering Information: 150 A active current See page 29. 60 nA standby current Applications Pin Assignments HVAC/R Micro-environments/data centers Thermostats/humidistats Automotive climate control and Top View defogging Respiratory therapy Asset and goods tracking White goods Mobile phones and tablets Indoor weather stations SDA 1 6 SCL Description GND 2 5 VDD 2 The Si7021 I C Humidity and Temperature Sensor is a monolithic CMOS IC integrating humidity and temperature sensor elements, an analog-to-digital 2 3 4 converter, signal processing, calibration data, and an I C Interface. The patented DNC DNC use of industry-standard, low-K polymeric dielectrics for sensing humidity enables the construction of low-power, monolithic CMOS Sensor ICs with low drift and hysteresis, and excellent long term stability. Patent Protected. Patents pending The humidity and temperature sensors are factory-calibrated and the calibration data is stored in the on-chip non-volatile memory. This ensures that the sensors are fully interchangeable, with no recalibration or software changes required. The Si7021 is available in a 3x3 mm DFN package and is reflow solderable. It can be used as a hardware- and software-compatible drop-in upgrade for existing RH/ temperature sensors in 3x3 mm DFN-6 packages, featuring precision sensing over a wider range and lower power consumption. The optional factory-installed cover offers a low profile, convenient means of protecting the sensor during assembly (e.g., reflow soldering) and throughout the life of the product, excluding liquids (hydrophobic/oleophobic) and particulates. The Si7021 offers an accurate, low-power, factory-calibrated digital solution ideal for measuring humidity, dew-point, and temperature, in applications ranging from HVAC/R and asset tracking to industrial and consumer platforms. Rev. 1.2 8/16 Copyright 2016 by Silicon Laboratories Si7021-A20Si7021-A20 Functional Block Diagram Vdd Si7021 1.25V Calibration Ref Memory Humidity Sensor Control Logic ADC Temp Sensor SDA 2 I C Interface SCL GND 2 Rev. 1.2