Data Sheet SHTC1 Humidity and Temperature Sensor IC Best performance-to-price ratio Fully calibrated and reflow solderable Ultra-low power consumption Power-up and measurement within 1 ms 1.8 V supply voltage Ultra-small DFN package: 2 × 2 × 0.75 mm Typical accuracy: ±3 %RH and ±0.3 °C Product Summary The SHTC1 is a digital humidity and temperature sensor designed especially for high-volume consumer electronics applications. This sensor is strictly designed to overcome conventional limits for size, power consumption, and performance to price ratio in order to fulfill current and future requirements. Sensirion’s CMOSens® technology offers a complete sensor system on a single chip, consisting of a capacitive humidity sensor, a bandgap temperature sensor, analog and digital signal processing, A/D converter, calibration data memory, and a digital communication interface supporting I2C fast mode. The ultra-small, 2 × 2 × 0.75 mm3 DFN package enables applications in even the most limited of spaces. Block diagram Benefits of Sensirion’s CMOSens® Technology The sensor covers a humidity measurement range of 0 to 100 %RH and a temperature measurement range of –30 to 100 °C with a typical accuracy of ±3 %RH and ±0.3°C. The operation voltage of 1.8 V and an energy budget below 1 µJ per measurement make the SHTC1 suitable for mobile or wireless applications running on the tightest power budgets. With the industry-proven quality and reliability of Sensirion’s humidity and temperature sensors and constant accuracy over a large measurement range, the SHTC1 offers an unprecedented performance-to-price ratio. Tape and reel packaging together with suitability for standard SMD assembly processes make the SHTC1 predestined for high-volume applications. High reliability and long-term stability Industry-proven technology with a track record of more than 10 years Designed for mass production Optimized for lowest cost Low signal noise Signal conditioning Signal conditioning Data processing and system control Calibration mem. VDD Figure 1 Functional block diagram of the SHTC1.

Humidity and Temperature Sensor Specifications Relative Humidity Long-term drift Table 2 Temperature sensor specifications. Table 1 Humidity sensor specifications. Maximum Accuracy Maximum accuracy Typical Accuracy Typical Accuracy Figure 2 Typical and maximal tolerance for relative humidity in %RH at 25 °C. Figure 3 Typical and maximal tolerance for temperature sensor in °C. For definition of typ. and max. accuracy tolerance, please refer to the document “Sensirion Humidity Sensor Specification Statement”. 2 The stated repeatability is 3 times the standard deviation (3σ) of multiple consecutive...

1.2 Recommended Operating Conditions 1.1 RH Accuracy at Various Temperatures The sensor shows best performance when operated within recommended normal temperature and humidity range of 5 – 60 °C and 20 – 80 %RH, respectively. Long term exposure to conditions outside normal range, especially at high humidity, may temporarily offset the RH signal (e.g. +3%RH after 60h at >80%RH). After returning into the normal temperature and humidity range the sensor will slowly come back to calibration state by itself. Prolonged exposure to extreme conditions may accelerate ageing. Typical RH accuracy at 25°C...

2.2 Absolute Maximum Ratings Stress levels beyond those listed in Table 4 may cause permanent damage to the device. These are stress ratings only and functional operation of the device at these conditions cannot be guaranteed. Exposure to the absolute maximum rating conditions for extended periods may affect the reliability of the device. Parameter Supply voltage, VDD Operating temperature range Storage temperature range11 ESD HBM ESD MM ESD CDM Latch up, JESD78 Class II, 125°C Table 4 Absolute maximum ratings. Timing Specifications 3.1 Sensor System Timings Default conditions of 25 °C and 1.8...

3.2 Communication Timings Default conditions of 25 °C and 1.8 V supply voltage apply to values in the table below, unless otherwise stated. Parameter SCL clock frequency Hold time (repeated) START condition LOW period of the SCL clock HIGH period of the SCL clock Set-up time for a repeated START condition SDA hold time SDA set-up time SCL/SDA rise time Symbol fSCL tLOW tHIGH Conditions After this period, the first clock pulse is generated - SCL/SDA fall time SDA valid time Set-up time for STOP condition Capacitive load on bus line Table 6 Communication timing specifications. The numbers above...

Interface Specifications The SHTC1 supports I2C fast mode (SCL clock frequency from 0 to 400 kHz) with clock stretching. For detailed information on the I2C protocol, refer to NXP I2C-bus specification and user manual UM10204, Rev. 4, February 13, 2012: http://ics.nxp.com/support/documents/interface/pdf/I2C.bu s.specification.pdf The SHTC1 comes in a 4-pin package – see Table 7. Pin Name Comments 1 VDD Supply voltage 2 SCL Serial clock, bidirectional 3 SDA Serial data, bidirectional 4 VSS Ground SCL is used to synchronize the communication between microcontroller and the sensor. The master must...

5.3 Starting a Measurement A measurement communication sequence consists of a START condition followed by the I2C header with the 7-bit I2C device address and a write bit (write W: ‘0’). The sensor indicates the proper reception of a byte by pulling the SDA pin low (ACK bit) after the falling edge of the 8th SCL clock. Then the sensor is ready to receive a 16-bit measurement command. Again, the SHTC1 acknowledges the proper reception of each byte with ACK condition. A complete measurement cycle is presented in Figure 7. With the acknowledgement of the measurement command, the SHTC1 starts measuring...

Property Name Width Polynomial Initialization Reflect input Reflect output Final XOR Examples compensated by the SHTC1. Humidity and temperature values can be calculated with the formulas in given below. Relative humidity conversion formula (result in %RH): Temperature conversion formula (result in °C): SRH and ST denote the raw sensor output (as decimal values) for humidity and temperature, respectively. 5.9 Conversion of Sensor Output Measurement data is always transferred as 16-bit values. These values are already linearized and temperature clock stretching disabled S 1 1 1 0 0 0 0 1 repeated...