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- HTU21D
HTU21D
HTU21D
- Interchangeable without calibration under standard conditions.
- Quick desaturation after saturation.
- Compatible with automated assembly, including Pb-free and reflow processes.
- Individually marked for traceability.
- Home Appliances
- Medical Devices
- Printers
- Humidifiers
The HTU21D(F) is a digital humidity sensor with temperature output, featuring a compact DFN package. It provides calibrated, linearized signals in digital I²C format, ideal for OEM applications requiring reliable measurements. It is designed for high volume, cost-sensitive applications with space constraints, offering low power consumption and fast response time.
- Storage Temperature: -40 to 125°C
- Supply Voltage (Peak): 3.8V
- Humidity Operating Range: 0 to 100% RH
- Temperature Operating Range: -40 to +125°C
- Humidity Accuracy: +/-3%RH max tolerance at 55%RH
- Voltage Supply: 1.5 to 3.6 V
- Current Consumption: 0.02 µA in sleep mode, 300-500 µA during measurement
- Communication: I²C protocol
- Humidity Resolution: 12 bits (0.04% RH), 8 bits (0.7% RH)
- Humidity Accuracy: ±2% RH typical at 25°C
- Temperature Resolution: 14 bit (0.01°C), 12 bit (0.04°C)
- Temperature Accuracy: ±0.3°C typical at 25°C
- Soldering: Lead-free reflow soldering recommended.
- Storage: Store in original packaging at -40°C to 125°C.
- Temperature Effects: Ensure sensors are at the same temperature as the air being measured.
- Wiring: Use shielded cables and bypass capacitors to improve signal integrity.
- Power Pins: Supply voltage range of 1.5VDC - 3.6VDC.
- Serial Clock Input (SCK): Synchronizes communication between microcontroller and sensor.
- Serial Data (DATA): Transfers data in and out of the device.
- Start-up: Requires a voltage supply between 1.5V and 3.6V, with a 15ms delay for idle state readiness.
- Commands: Initiated with a start bit and concluded with a stop bit.
- Hold Master Mode: The sensor controls the SCK line, forcing the master into a wait state during measurement.
- No Hold Master Mode: The MCU polls the sensor for measurement completion, allowing other I²C tasks to proceed.
- Temperature Measurement: 0xE3 (Hold), 0xF3 (No Hold)
- Humidity Measurement: 0xE5 (Hold), 0xF5 (No Hold)
- Write User Register: 0xE6
- Read User Register: 0xE7
- Soft Reset: 0xFE
- Relative Humidity: Calculated using the formula RH = (SRH/65536) * 125 - 6.
- Temperature: Calculated using the formula Temp = (STemp/65536) * 175.72 - 46.85.
The HTU21D(F) sensor is packaged in a Dual Flat No leads (DFN) format, with dimensions given in millimeters and tolerances of ±0.1mm. The die pad is internally connected to GND. The sensor is mounted on a Cu lead frame plated with Ni/Pd/Au and over-molded with green epoxy-based compound. The total weight is 0.025g.
Each sensor is laser marked with a five-digit alphanumeric code. The first line indicates the sensor type (HTU21), and the second line provides output mode, manufacturing year, and a tracking code. Reels are labeled with additional traceability information including sensor type, output mode, PTFE membrane option, traceability code, quantity per reel, and manufacturing date.
Sensors are shipped in tape and reel packaging, sealed in antistatic ESD bags. Standard reel sizes are 400, 1500, and 5000 units. Packaging includes header and trailer tapes. Reels for 400 and 1500 units have a 7” diameter, while 5000-unit reels have a 13” diameter.
Sensors should be stored in original sealed anti-ESD packaging or anti-static shielded ESD bags if removed. Classified as MSL level 1, they have a recommended shelf life of 1 year under ≤30°C and 85%RH.
Available in tape and reel packaging with options for 400, 1500, or 5000 pieces. Part numbers differ based on quantity and PTFE membrane option. Demo kits are available for Android/iOS and Windows PC.
The document has undergone several updates, including corrections to I²C communication, soldering temperature, and the addition of diagnostic and ordering information.
TE Connectivity provides contact details for North America, Europe, and Asia for customer support.
Catalog excerpts
FEATURES • Full interchangeability with no calibration required in standard conditions • Instantaneous desaturation after long periods in saturation phase • Compatible with automatized assembly processes, including Pb free and reflow processes • Individual marking for compliance to stringent traceability requirements APPLICATIONS • Home Appliance • Medical • Printers • Humidifier HTU21D(F) RH/T SENSOR IC Digital Relative Humidity sensor with Temperature output • DFN type package • Relative Humidity and Temperature Digital Output, I2C interface • Fully calibrated • Lead free sensor, reflow solderable • Low power consumption • Fast response time The HTU21D(F) is a new digital humidity sensor with temperature output by MEAS. Setting new standards in terms of size and intelligence, it is embedded in a reflow solderable Dual Flat No leads (DFN) package with a small 3 x 3 x 0.9 mm footprint. This sensor provides calibrated, linearized signals in digital, I2C format. HTU21D(F) digital humidity sensors are dedicated humidity and temperature plug and play transducers for OEM applications where reliable and accurate measurements are needed. Direct interface with a micro-controller is made possible with the module for humidity and temperature digital outputs. These low power sensors are designed for high volume and cost sensitive applications with tight space constraints. Every sensor is individually calibrated and tested. Lot identification is printed on the sensor and an electronic identification code is stored on the chip - which can be read out by command. Low battery can be detected and a checksum improves communication reliability. The resolution of these digital humidity sensors can be changed by command (8/12bit up to 12/14bit for RH/T). With MEAS' improvements and miniaturization of this sensor, the performance-to-price ratio has been improved - and eventually, any device should benefit from its cutting-edge energy saving operation mode. Optional PTFE filter/membrane (F) protects HTU21D digital humidity sensors against dust and water immersion, as well as against contamination by particles. PTFE filter/membranes preserve a high response time. The white PTFE filter/membrane is directly stuck on the sensor housing. This membrane is allowing an IP67 compliant protection. TE CONNECTIVITY SENSORS /// HTU21D(F) RH/T SENSOR IC
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Digital Relative Humidity sensor with Temperature output > With embedded PTFE filter: HTU2XYF > Output Sensor: Y = D/A for Digital, I2C protocol = P for PWM interface, analog output Humidity accuracy: X = 0: +/-5%RH max tolerance @55%RH = 1: +/-3%RH max tolerance @55%RH Maximum Ratings Graph above show peak conditions: less than 10% of the operating life Exposure to absolute maximum rating conditions for extended periods may affect the sensor reliability. TE CONNECTIVITY SENSORS /// HTU21 D(F) RH/T SENSOR IC
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Digital Relative Humidity sensor with Temperature output (1) Typical values are recommended for calculating energy consumption while maximum values shall be applied for calculating waiting times in communication. (2) At 1 m/s air flow TE CONNECTIVITY SENSORS /// HTU21 D(F) RH/T SENSOR IC
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HTU21D(F) RH/T SENSOR IC Digital Relative Humidity sensor with Temperature output GRAPH 1 : RELATIVE HUMIDITY ERROR BUDGET CONDITIONS AT 25°C Delta Relative Humidity (%RH) 10 Maximal Tolerance Typical Tolerance ▪ HTU21D(F) sensors are specified for optimum accuracy measurements within 5 to 95%RH. ▪ Operation out of this range (< 5% or > 95% RH, including condensation) is however possible. TEMPERATURE COEFFICIENT COMPENSATION EQUATION For other temperatures than 25°C, the following temperature coefficient compensation equation can be used and will guarantee Relative Humidity accuracy given in...
Open the catalog to page 4
Digital Relative Humidity sensor with Temperature output (1) Typical values are recommended for calculating energy consumption while maximum values shall be applied for calculating waiting times in communication. (2) At 1 m/s air flow Maximal Tolerance TE CONNECTIVITY SENSORS /// HTU21 D(F) RH/T SENSOR IC
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HTU21D(F) RH/T SENSOR IC Digital Relative Humidity sensor with Temperature output USER GUIDE HTU21D(F) Application Information • Soldering instructions: Lead free reflow soldering recommended process For soldering HTU21D (F) sensor standard reflow soldering ovens may be used. HTU21D(F) sensor as a humidity sensitive component (as classified by IPC/JEDEC J-STD-020 or equivalent documented procedure with peak temperature at 260°C during up to 30 seconds for Pb-free assembly in IR/convection reflow ovens) must be handled in a manner consistent with IPC/JEDEC J-STD-033 or an equivalent documented...
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HTU21D(F) RH/T SENSOR IC Digital Relative Humidity sensor with Temperature output In no case, neither after manual nor reflow soldering, a board wash shall be applied. Therefore, it is strongly recommended to use a “no-clean” solder paste. In case of applications with exposure of the sensor to corrosive gases or condensed water (i.e. environments with high relative humidity) the soldering pads shall be sealed (e.g. conformal coating) to prevent loose contacts or short cuts. Storage Conditions and Handling Instructions It is recommended to store HTU21D(F) sensor in its original packaging at following...
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Digital Relative Humidity sensor with Temperature output INTERFACE SPECIFICATION HTU21 D3157 Typical application circuit, including pull-up resistor Rp and decoupling of VDD and GND by a capacitor. • Power Pins (VDD, GND) The supply voltage of HTU21D(F) sensors must be in the range of 1.5VDC - 3.6VDC. Recommended supply voltage is 3VDC (regulated). However the typical application circuit includes a pull-up resistor R on data wire and a 100nF decoupling capacitor between VDD and GND, placed as close as possible to the sensor. • Serial clock input (SCK) SCK is used to synchronize the communication...
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