DatasheetHTE501 Digital Humidity and Temperature Sensor

Datasheet HTE501 Introduction to the E+E Digital Humidity and Temperature Sensor HTE501 Digital Humidity and Temperature Sensor The next generation of digital RH/T sensor combines accuracy and reliability to meet the highest current and future requirements. The integrated constant current heater as well as the innovative and proven E+E proprietary coating ensures outstanding performance even in harsh environments. In a DFN package with a footprint of only 2.5 x 2.5 mm, the HTE501 provides an exceptional accuracy of up to ±1.8 %RH incl. hysteresis, paired with dew point calculation and a maximum...

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Table 1: List of HTE501 specific acronyms v1.7 / Modification rights reserved | 5

Bottom view Thermal pad internally connected to GND Figure 1: DFN8 pin configuration Serial data line for I2C communication Output open drain Indicates heater status and measurement invalid1) Input high-Z I2C device address pin, bit 1 of the 7 bit address; do not leave floating Serial clock line for I2C communication Input high-Z I2C device address pin, bit 2 of the 7 bit address; do not leave floating Input high-Z I2C device address pin, bit 3 of the 7 bit address; do not leave floating Ground (internally connected to thermal pad)2) 1) If unused see pin description (HI Pin). 2) S oldering of...

3 Specification 3.1 Relative Humidity Sensor Table 4: Temperature sensor parameters 1) In the periodic mode the humidity hysteresis is included. See also chapter 3.3 Recommended Operating Conditions. 2) In the periodic mode the humidity accuracy is within the hysteresis. In the single shot measurement, the humidity hysteresis must be added to the given humidity accuracy to obtain the overall accuracy. 3) The detailed definition of “typ.” and “max.” is given in the document Sensor Specification Accuracy, available at www.epluse.com/hte501. 4) Default resolution is 13 bit temperature / 13 bit humidity....

3.3 Recommended Operating Conditions The sensor shows best performance when operated within the normal operating conditions (dark green area in Figure 5). This means 20...80 %RH, temperature >0 °C and dew point temperature <60 °C. Exposure conditions outside this “Normal operating condition” for a long time, especially at high humidity >80 %RH may cause a temporary humidity gain error. If the sensor is brought back to normal operating conditions, the initial values will recover. Applications with high humidity at high temperatures will result in slower recovery. Reconditioning procedures can...

4.1 Absolute Maximum Ratings 1) Without I2C communication and when not measuring. 2) The chip temperature must not exceed 135°C with heater on. For example VDD = 3.3 V, heater current = 80 mA ^ Pheat = 0.264 W ^ Overtemperature ~40 °C (Rth ~ 150 K/W) ^ Ambient temperature < 95 °C ^ check the measured temperature while constant current heater is on. Table 6: General operation v1.7 / Modification rights reserved | 9

Table 9: General timing Subsequently, the typical time from VDD > VPORP to measurement ready in the standard configuration is: tRDY= tPWRU + tMEAS = tPWRU + tT + tRH + tCALC = 15.3 ms v1.7 / Modification rights reserved | 10

Table 10: Measurement resolution 5.1 Pin Configuration, Assignment and Description Please refer to chapter 1. The supply pins must be equipped with a bypass ceramic capacitor of at least 100 nF. When using the constant current heater, a current change in the heater must not lead to a voltage drop below the minimum VDD value (refer to Table 6). This means the bypass capacitor needs to be dimensioned sufficiently large so that the voltage controller is supplied adequately. Sensor Power-up As soon as VDD exceeds the POR voltage VPORP, the device gets initialized. After tPWRU, the initialization...

Datasheet HTE501 F:\proj\P\2016\P201607_EuE_ASIC_ASTRID1\04_DOC\Berechnungen\PWRup_HIpin_Modi Voltage VDD 3.3V VPORP tMEAS Automatic measurement at power-up IDLE MODE Figure 7: Sensor behaviour at power-up The I²C communication is based on the NXP UM10204 I²C bus specification and user manual1). The HTE501 supports the modes “standard“ (100 kHz), “fast mode“(400 kHz) and “fast mode plus” (1 000 kHz). The sensor works as SLAVE and needs to be queried by a MASTER. Please consider self-heating due to a low RPU when the sensor has to sink the pull-up current. In this case, the residual voltage on...

The HI pin means “Heater/Invalid” and it indicates that the measurement does not show the real environmental humidity and temperature conditions: 1. Internal heater on: the internal heater starts a self-heating, and therefore the temperature is higher and the humidity is lower than the surrounding environmental conditions actually are. b. Heater OFF (command 0x3066) ^ pin = high-Z 2. Recent measurement was invalid: a. Recent measurement (temperature or/and humidity) was: The status of each measurement (valid/invalid) can be read out from the status register 2. b. During power up until the start-up...

Measured Data Format Measurement Modes There are two different operation modes to communicate with the sensor: 1.shotSingle Single mode Shot Measurement G:\Produkte\HTEx01\501\Archive_Diagrams&Drawings\PWRup_HIpin_Modi Time depends on COMMAND Time depends on COMMAND READ Measurement READ Measurement time time IDLE MODE COMMAND COMMAND Break Break Measurement Measurement IDLE MODE tMEAS tMEAS tMEAS Time depends on measurement Time depends on measurement interval, 1 s at start‐up interval, 1 s at start‐up tMEAS tMEAS tMEAS Time depends on measurement Time depends on measurement interval, 1 s at...

MEASUREMENT ONGOING tMEAS N P single shot 1 10: Start Figure 1 Without clock stretching MEASUREMENT FINISHED 16 BIT COMMAND measurement readout 16 BIT COMMAND Without clock stretching W FREE A A FOR OTHER CMD MSBBUS MEMBERS I2C-ADDRESS SCL S 0 0 0 SCL FREE FOR OTHER BUS MEMBERS A 4 3LSB 2 1 0 7 6 5 CMD W A A Figure Clock stretching during measurement CMD MSB I2C-ADDRESS S 11: CMD LSB MEASUREMENT ONGOING 0 0 0 16 BIT COMMAND MEASUREMENT FINISHED MEASUREMENT ONGOING tMEAS In case a command with clock stretching enabled has been issued, the slave holds SCL low until the calculation has been With...