Sensirion SHT40 Temperature & Humidity Sensor I2C DFN

The Sensirion SHT40-AD1B-R2 is a high-accuracy digital sensor platform for measuring relative humidity and temperature in demanding environments. Designed for surface mount technology (SMT) processing, its four-pin dual-flat-no-leads (DFN) package ensures reliable integration into compact electronic assemblies.

With a relative humidity accuracy of up to ±1.5 %RH and a temperature accuracy of up to ±0.1 °C, the sensor delivers precise data for critical applications. It operates across a supply voltage range of 1.08V to 3.6V and consumes an ultra-low average current of 0.4µA (at a measurement rate of 1Hz), making it ideal for battery-powered devices. The idle current is a mere 80nA, further extending battery life.

The I2C interface supports fast mode plus and includes a CRC checksum for data integrity. Multiple preconfigured I2C addresses allow flexible system design. The internal power-trimmed heater offers three heating levels, enabling reliable operation in condensing or demanding conditions. The sensor is fully functional across 0 to 100 %RH and -40 to 125 °C, and features NIST traceability for measurement confidence.

Key Specifications:

• Humidity range: 0% to 100% relative humidity
• Humidity accuracy: ±1.8% RH
• Temperature accuracy: ±0.2°C
• Response time: 8s (RH), 2s (temperature)
• Interface: I2C fast mode plus, CRC checksum
• Package: DFN, 4 pins
• Supply voltage: 1.08V to 3.6V

This sensor is well-suited for HVAC, weather stations, and industrial monitoring systems requiring precise and low-power environmental sensing.