Overview: The SHT7x series, including models SHT71 and SHT75, are humidity and temperature sensor ICs by Sensirion. These sensors are fully calibrated, offer digital output, low power consumption, and excellent long-term stability, designed for easy integration with a pin-type package.

Specifications: The sensors feature a version 4 silicon chip with integrated humidity and temperature sensors, amplifier, A/D converter, OTP memory, and digital interface. They comply with RoHS and WEEE standards, being free from hazardous substances like Pb, Cd, and Hg.

Performance: The sensors provide a resolution of 12-bit for humidity and 14-bit for temperature. The SHT71 has a typical humidity accuracy of ±3.0% RH, while the SHT75 offers ±1.8% RH. Temperature accuracy is ±0.4°C for SHT71 and ±0.3°C for SHT75. The operating range for humidity is 0-100% RH and for temperature is -40 to 123.8°C.

Electrical Characteristics: The sensors operate with a source voltage between 2.4V and 5.5V, with a recommended supply voltage of 3.3V. Power consumption ranges from 2 µW in sleep mode to 3 mW during measurement.

Interface: The SHT7x uses a 2-wire digital interface with pin assignments: 1 - SCK (Serial Clock), 2 - VDD (Source Voltage), 3 - GND (Ground), 4 - DATA (Serial Data). A 100nF capacitor is integrated for decoupling VDD and GND.

Application Information: Direct soldering is not recommended; sockets should be used. Sensors should be stored in ESD bags and handled carefully to avoid exposure to chemical vapors. A reconditioning procedure is available for sensors exposed to extreme conditions.

Packaging: The SHT71 and SHT75 are available in tape stripes, each containing 50 units.

Additional Notes: The sensors are not light-sensitive, but prolonged exposure to UV radiation may age the housing. Proper wiring and signal integrity practices are essential to avoid communication issues.

Specifications and Signal Characteristics: The document outlines the I/O signal characteristics, including a requirement that the slew rate during power-up should not fall below 1V/ms. The sensor requires 11ms to reach Sleep State after power-up, during which no commands should be sent.

Communication with Sensor:

• Start-up: The sensor is powered up to a chosen supply voltage VDD.
• Sending a Command: A Transmission Start sequence is required, involving specific manipulations of the DATA and SCK lines. Commands consist of three address bits and five command bits, with the sensor acknowledging receipt by pulling the DATA pin low.
• Measurement of RH and T: After issuing a measurement command, the controller waits for the measurement to complete, which varies in time based on the bit resolution. The sensor signals completion by pulling the data line low.
• Connection Reset Sequence: If communication is lost, a specific signal sequence can reset the serial interface.
• CRC-8 Checksum: An optional feature to ensure data integrity during transmission.
• Status Register: Allows activation of advanced functions like measurement resolution and heater use.

Conversion of Signal Output:

• Relative Humidity: Non-linearity compensation is recommended using specific formulas and coefficients.
• Temperature Compensation: Necessary for humidity signals at temperatures significantly different from 25°C.
• Temperature: Conversion from digital readout to temperature value is linear, with specific coefficients provided.
• Dew Point: Calculated from humidity and temperature readings using an approximation formula.

Environmental Stability: The sensor's performance is tested under specific conditions, such as high temperature and humidity, and is compliant with various standards.

Packaging: The sensor is supplied in a single-in-line pin type package, compliant with RoHS and WEEE standards. Traceability is ensured through alphanumeric codes on the chip cap and labels on reels.

Shipping Package: Sensors are shipped in 32mm tape with specific packaging details provided.

Revision History: The datasheet for the SHT7x series has undergone several revisions, with the latest version being 5, released in December 2011. Key changes include the elimination of references to V3 sensors and various updates and corrections over previous versions.

Important Notices: The document emphasizes that the SHT7x should not be used in safety-critical applications where failure could result in personal injury. It also highlights the need for compliance with ESD precautions to prevent damage to the component. The warranty is limited to 12 months and covers defects in design, material, or workmanship, provided certain conditions are met.

Warranty Details: Sensirion offers a 12-month warranty from the date of delivery, covering defects due to faulty design, material, or workmanship. The warranty requires written notice of defects within 14 days of appearance and return of the product at the buyer's expense. The warranty does not cover improper use or installation outside recommended specifications.

Contact Information: Sensirion provides contact details for its headquarters in Switzerland and subsidiaries in the USA, Japan, Korea, China, and Germany. Customers are encouraged to visit the Sensirion website for local representative information.