Datasheet SHT7x (SHT71, SHT75) Humidity and Temperature Sensor IC Fully calibrated Digital output Low power consumption Excellent long term stability Pin type package easy integration Product Summary Each SHT7x is individually calibrated in a precision SHT7x (including SHT71 and SHT75) is Sensirions family humidity chamber. The calibration coefficients are of relative humidity and temperature sensors with pins. programmed into an OTP memory on the chip. These The sensors integrate sensor elements plus signal coefficients are used to internally calibrate the signals processing in compact format and provide a fully from the sensors. The 2-wire serial interface and internal calibrated digital output. A unique capacitive sensor voltage regulation allows for easy and fast system element is used for measuring relative humidity while integration. The small size and low power consumption temperature is measured by a band-gap sensor. The makes SHT7x the ultimate choice for even the most applied CMOSens technology guarantees excellent demanding applications. reliability and long term stability. Both sensors are seamlessly coupled to a 14bit analog to digital converter SHT7x is supplied on FR4 with pins which allows for easy and a serial interface circuit. This results in superior signal integration or replacement. The same sensor is also quality, a fast response time and insensitivity to external available as surface mountable packaging (SHT1x) or on disturbances (EMC). flex print (SHTA1). Dimensions Sensor Chip 3.1 SHT7x V4 for which this datasheet applies features a 2.2 3.7 version 4 Silicon sensor chip. Besides a humidity and a temperature sensor the chip contains an amplifier, A/D converter, OTP memory and a digital interface. V4 sensors B2G can be identified by the alpha-numeric traceability code on the sensor cap see example B2G code on Figure 1. 71 0.6 1.2 Material Contents While the sensor is made of a CMOS chip the sensor 1 2 3 4 housing consists of an LCP cap with epoxy glob top on an FR4 substrate. Pins are made of a Cu/Be alloy coated with Ni and Au. The device is fully RoHS and WEEE compliant, thus it is free of Pb, Cd, Hg, Cr(6+), PBB and PBDE. Evaluation Kits 0.46 1.27 0.2 For sensor trial measurements, for qualification of the 5.08 2.0 sensor or even experimental application (data logging) of the sensor there is an evaluation kit EK-H4 available Figure 1: Drawing of SHT7x (applies to SHT71 and SHT75) including SHT71 (same sensor chip as SHT1x) and 4 sensor packaging, dimensions in mm (1mm = 0.039inch). sensor channels, hard and software to interface with a Contact assignment: 1: SCK, 2: VDD, 3: GND, 4: DATA. computer. For other evaluation kits please check Hatched item on backside of PCB is a 100nF capacitor see www.sensirion.com/humidity. Section 2.1 for more information. www.sensirion.com Version 5 December 2011 1/12 19.5 6.0 3.4 3.7 6.4 13.5 0.4 Datasheet SHT7x Sensor Performance 12 45 Relative Humidity Temperature Parameter Condition min typ max Units Parameter Condition min typ max Units 0.4 0.05 0.05 %RH 0.04 0.01 0.01 C 1 1 Resolution Resolution 8 12 12 bit 12 14 14 bit 2 2 typ %RH typ C 3.0 0.4 Accuracy Accuracy SHT71 SHT71 max see Figure 2 max see Figure 3 2 2 typ %RH typ C 1.8 0.3 Accuracy Accuracy SHT75 SHT75 max see Figure 2 max see Figure 3 Repeatability 0.1 %RH Repeatability C 0.1 Hysteresis %RH -40 123.8 C 1 Operating Range -40 254.9 F raw data 3 %RH Nonlinearity 6 Response Time tau 63% 5 30 s linearized <<1 %RH 3 Long term drift < 0.04 C/yr Response time tau 63% 8 s Operating Range 0 100 %RH 4 Long term drift normal < 0.5 %RH/yr 6 3.0 2.5 4 2.0 SHT71 SHT71 1.5 2 1.0 SHT75 SHT75 0.5 0 0.0 0 10 20 30 40 50 60 70 80 90 100 -40 -20 0 20 40 60 80 100 Relative Humidity (%RH) Temperature (C) Figure 2: Maximal RH-tolerance at 25C per sensor type. Figure 3: Maximal T-tolerance per sensor type. Electrical and General Items Packaging Information Parameter Condition min typ max Units Sensor Type Packaging Quantity Order Number SHT71 Tape Stripes 50 1-100092-04 Source Voltage 2.4 3.3 5.5 V sleep 2 5 W SHT75 Tape Stripes 50 1-100071-04 Power measuring 3 mW 5 Consumption average 90 W This datasheet is subject to change and may be Communication digital 2-wire interface, see Communication amended without prior notice. Storage 10 50C (0 80C peak), 20 60%RH 1 4 The default measurement resolution of is 14bit for temperature and 12bit for Value may be higher in environments with high contents of volatile organic humidity. It can be reduced to 12/8bit by command to status register. compounds. See Section 1.3 of Users Guide. 2 5 Accuracies are tested at Outgoing Quality Control at 25C (77F) and 3.3V. Values for VDD=3.3V at 25C, average value at one 12bit measurement Values exclude hysteresis and are only applicable to non-condensing per second. environments. 6 Response time depends on heat capacity of and thermal resistance to 3 Time for reaching 63% of a step function, valid at 25C and 1 m/s airflow. sensor substrate. www.sensirion.com Version 5 December 2011 2/12 DRH (%RH) DT (C)