GY-21 SI7021 High Precision Temperature and humidity sensor module

The Si7021 I2C Humidity and Temperature Sensor is a monolithic CMOS IC integrating humidity and temperature sensor elements, an analog-to-digital converter, signal processing, calibration data, and an I2C Interface. The patented 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.

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 3×3 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 3×3 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.

Technical Specifications:

• Supply Power 3-5v
• Precision Relative Humidity Sensor: ± 3% RH (max), 0-80% RH
• High Accuracy Temperature Sensor: ±0.4 °C (max), -10 to 85 °C
• 0 to 100% RH operating range
• Up to -40 to +125 °C operating range
• Wide operating voltage (1.9 to 3.6 V)
• Low Power Consumption 150 μA active current
• 60 nA standby current
• Factory-calibrated
• I2C Interface
• Integrated on-chip heater
• 3×3 mm DFN Package
• Excellent long term stability
• Optional factory-installed cover
• Low-profile
• Protection during reflow
• Excludes liquids and particulates

Applications:

HVAC/R

Thermostats/humidistats

Respiratory therapy

White goods

Indoor weather stations

Micro-environments/data centers

Automotive climate control and defogging

Asset and goods tracking

Mobile phones and tablets