Digital Humidity Sensor SHT3x (RH/T)
Best-In-Class Humidity Sensor For Various Applications
The new digital SHT3x humidity sensor series takes sensor technology to a new level. As the successor of the SHT2x series it is determined to set the next industry standard in humidity sensing. The SHT3x humidity sensor series consists of a low-cost version with the SHT30 humidity sensor, a standard version with the SHT31 humidity sensor, and a high-end version with the SHT35 humidity sensor. The SHT3x humidity sensor series combines multiple functions and various interfaces (I2C, analog voltage output) with a applications-friendly, very wide operating voltage range (2.4 to 5.5 V). The SHT3x humidity sensor is available in both large and small volumes.
The SHT3x builds on a completely new and optimized CMOSens® chip, which allows for increased reliability and improved accuracy specifications. The SHT3x offers a range of new features, such as enhanced signal processing, two distinctive and user-selectable I2C addresses, an alert mode with programmable humidity and temperature limits, and communication speeds of up to 1 MHz.
The DFN package has a footprint of 2.5 × 2.5 mm2 with a height of 0.9 mm. This allows for integration of the SHT3x into a great variety of applications. Additionally, the wide supply voltage range of 2.4 to 5.5 V and variety of available interfaces guarantee compatibility with diverse integration requirements. All in all, the SHT3x humidity sensor series incorporates 15 years of knowledge from Sensirion, the leader in the humidity sensor industry.
Overview of SHT3x Versions
|VDD Range (V)||Interface||Protective Options||Available Reel Sizes (pcs)|
|2.4 to 5.5||analog ratiometric voltage||-||10'000|
|2.4 to 5.5||I2C||-||10'000|
|2.4 to 5.5||analog ratiometric voltage||-||2'500, 10'000|
|2.4 to 5.5||I2C||-||2'500, 10'000|
|2.4 to 5.5||I2C||Filter membrane||2'500, 10'000|
|2.4 to 5.5||I2C||Protective cover||2'500, 10'000|
|2.4 to 5.5||I2C||-||2'500,|
|2.4 to 5.5||I2C||Filter membrane|| 2'500,|
|Size||2.5 x 2.5 x 0.9 mm|
|Output||I²C, Voltage Out|
|Supply voltage range||2.4 to 5.5 V|
|Energy consumption||4.8µW (at 2.4 V, low repeatability, 1 measurement / s)|
|RH operating range||0 - 100% RH|
|T operating range||-40 to +125°C (-40 to +257°F)|
|RH response time||8 sec (tau63%)|
|Packaging||Tape & Reel, sealed in ESD bag|
2'500 & 10'000 pieces per reel
Accuracy Limits for Relative Humidity and Temperature
Filter Membrane Option
The SHT3x membrane is an PTFE film that protects the sensor opening from water and dust according to IP67. It thus allows sensor use under harsh environmental conditions, where spray water and high exposure to dust might be challenging for accurate sensor performance. The membrane cover is attached to the sensor package by a double-faced adhesive tape, which is designed to stay on the package over the lifetime of the sensor. The whole package withstands multiple reflow cycles.
Due to minimal package volume and the membrane’s high water vapor permeability, the response time of the relative humidity and temperature signal is identical to the value achieved by the uncovered sensor. Although the membrane option provides perfect protection against water and dust ingress according to IP67, it does not in general prevent contamination from volatile chemicals. More details on contamination can be found in the document "Handling Instructions for Humidity Sensors". All SHT3x sensors can be ordered in tape and reel packaging; the reels are delivered in sealed antistatic ESD bags. Please find more details in the relevant datasheet.
The SHT3x protective cover is an optional polyimide foil directly attached to the top surface of the sensor. It covers the SHT3x’s complete sensing area and thus acts as a reliable shield against pollution during SMT assembly of the sensor and subsequent processes, such as conformal coating or potting. The protective cover is designed to withstand multiple reflow soldering cycles. To enable correct sensor operation, it must be removed after assembly.
A flap on the cover extends over the outer dimensions of the sensor package on one side and is designed to allow the cover to be peeled off easily with tweezers. After peeling off, the sensor will operate as specified in the datasheet. All typical conformal coating procedures, such as brushing, spraying or potting, can be used as long as the protective cover is attached. The cover will effectively protect the sensor opening from direct exposure to these coatings and other possible pollutants during the production process. Please find more details in the relevant datasheet.
Development Kit: SHT31 Smart Gadget
The SHT31 Smart Gadget is a simple reference design circuit board and development kit which demonstrates the outstanding performance and ease of use of Sensirion’s humidity and temperature sensors. The Smart Gadget not only shows humidity and temperature values on the display, but can also communicate with a bluetooth SMART capable device like a smartphone. For developers, full design resources of the SHT31 Smart Gadget are available on GitHub.
- SHT31 humidity sensor
- LCD display for humidity, temperature and dew point in °C and °F
- Bluetoogh Low Energy (BLE) connectivity to iOS and Android smartphones
- iOS and Android apps available
- Data logging capabilities
- Complete hardware, firmware and software design resources available