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Technical content

Features

 Precision Relative Humidity Sensor  ± 2.0% RH (Typ), 0–80% RH  High Accuracy Temperature Sensor  0 to 100% RH operating range  –40 to +85 °C operating range  Wide operating voltage (1.9 to 3.6 V)  Low Power Consumption  150 µA active current  60 nA standby current

Applications

 HVAC/R  Thermostats/humidistats  Respiratory therapy  White goods  Indoor weather stations

Description

 Factory-calibrated  I2C Interface  Integrated on-chip heater  9.1mmx10.8 mm SMT Module  Excellent long term stability  Optional factory-installed cover  Low-profile  Protection during reflow  Excludes liquids and particulates  Micro-environments/data centers  Automotive climate control and defogging  Asset and goods tracking  Mobile phones and tablets TH08: 9.1mmx10.8 mm SMT Module The TH08 I2C Humidity and Temperature Sensor is a monolithic CMOS IC integrating humidity and temperature sensor elements, an analog-to-digital converter, signal processing, calibration data, and an I2C Interface. The patented use of industry-standard, low-K polymeric dielectrics for sensing humidity enables the construction of low- power, monolithic CMOS Sensor ICs with low drift and hysteresis, and excellent long term stability. The humidity and temperature sensors are factory-calibrated and the calibration data is stored in the on-chip non- volatile memory. This ensures that the sensors are fully interchangeable, with no recalibration or software changes required The TH08 is reflow solderable. It can be used as a hardware- and software-compatible drop-in upgrade for existing RH/ temperature sensors , featuring precision sensing over a wider range and lower power consumption. The optional factory-installed cover offers a low profile, convenient means of protecting the sensor during assembly (e.g., reflow soldering) and throughout the life of the product, excluding liquids (hydrophobic/oleophobic) and particulates. The TH08 offers an accurate, low-power, factory-calibrated digital solution ideal for measuring humidity, dew-point, and temperature, in applications ranging from HVAC/R and asset tracking to industrial and consumer platforms.

  1. Electrical Specifications

Unless otherwise specified, all min/max specifications apply over the recommended operating conditions. Table 1. Recommended Operating Conditions Table 2. General Specifications 1.9 < VDD < 3.6 V; TA = –40 to 125 °C default conversion time unless otherwise noted.

  1. Initiating a RH measurement will also automatically initiate a temperature measurement. The total conversion time will
  2. No conversion or I2C transaction in progress. Typical values measured at 25 °C.
  3. Occurs once during powerup. Duration is <5 msec.
  4. Occurs during I2C commands for Reset, Read/Write User Registers, Read EID, and Read Firmware Version. Duration is

<100 µs when I2C clock speed is >100 kHz (>200 kHz for 2-byte commands).

  1. IDD after a user register write. Initiating any other subsequent I2C transaction on the same bus (such as the user
  2. Additional current consumption when HTRE bit enabled. See section “5.5. Heater” for more information

Table 2. General Specifications (Continued) 1.9 < VDD < 3.6 V; TA = –40 to 125 °C default conversion time unless otherwise noted.

  1. Initiating a RH measurement will also automatically initiate a temperature measurement. The total conversion time will
  2. No conversion or I2C transaction in progress. Typical values measured at 25 °C.
  3. Occurs once during powerup. Duration is <5 msec.
  4. Occurs during I2C commands for Reset, Read/Write User Registers, Read EID, and Read Firmware Version. Duration is

<100 µs when I2C clock speed is >100 kHz (>200 kHz for 2-byte commands).

  1. IDD after a user register write. Initiating any other subsequent I2C transaction on the same bus (such as the user
  2. Additional current consumption when HTRE bit enabled. See section “5.5. Heater” for more information

Table 3. I2C Interface Specifications1 1.9 ≤ VDD ≤ 3.6 V; TA = –40 to +125 °C unless otherwise noted.

  1. All values are referenced to VIL and/or VIH.
  2. Depending on the conversion command, the TH08 may hold the master during the conversion (clock stretch). At

highest I2C speed of 400 kHz the stretching will be <10 µs.

  1. Pulses up to and including 50 ns will be suppressed.

Table 3. I2C Interface Specifications1 (Continued) 1.9 ≤ VDD ≤ 3.6 V; TA = –40 to +125 °C unless otherwise noted.

  1. All values are referenced to VIL and/or VIH.
  2. Depending on the conversion command, the TH08 may hold the master during the conversion (clock stretch). At

highest I2C speed of 400 kHz the stretching will be <10 µs.

  1. Pulses up to and including 50 ns will be suppressed.

Figure 1. I2C Interface Timing Diagram

Table 4. Humidity Sensor 1.9 ≤ VDD ≤ 3.6 V; TA = 30 °C; default conversion time unless otherwise noted.

  1. Recommended humidity operating range is 20% to 80% RH (non-condensing) over –10 °C to 60 °C. Prolonged

operation beyond these ranges may result in a shift of sensor reading, with slow recovery time.

  1. Excludes hysteresis, long term drift, and certain other factors and is applicable to non-condensing environments only.

See section “4.1. Relative Humidity Sensor Accuracy” for more details.

  1. Drift due to aging effects at typical room conditions of 30 °C and 30% to 50% RH. May be impacted by dust, vaporized
  2. Response time to a step change in RH. Time for the RH output to change by 63% of the total RH change.

Figure 2. RH Accuracy at 30 °C

Table 5. Temperature Sensor 1.9 ≤ VDD ≤ 3.6 V; TA = –40 to +125 °C default conversion time unless otherwise noted.

  1. 14b measurement resolution (default).
  2. Time to reach 63% of final value in response to a step change in temperature. Actual response time will vary

dependent on system thermal mass and air-flow. Figure 3. Temperature Accuracy

Table 6. Absolute Maximum Ratings1

  1. Absolute maximum ratings are stress ratings only, operation at or beyond these conditions is not implied and may

shorten the life of the device or alter its performance.

  1. Typical Application Circuits

typical application circuit to achieve these functions. Figure 4. Typical Application Circuit for Relative Humidity and Temperature Measurement

Table 7. Typical Application Circuit BOM for Relative Humidity and Temperature Measurement

Figure 5. TH08 Block Diagram instrumentation, high reliability automotive and industrial systems, and cost-sensitive consumer electronics.  The need to protect the senor from damage or contamination during the product life-cycle.  The effects of humidity sensor “memory”. Each of these items is discussed in more detail in the following sections.

Sensor Accuracy Including Hysteresis,” shows the result of a typical sweep. Figure 6. Measuring Sensor Accuracy Including Hysteresis  Contamination of the sensor by particulates, chemicals, etc. temperature by less than ± 0.05% ° C.

Tel:+86-755-82973805 Fax: +86-755-82973550 Email:sales@hoperf.com http://www.hoperf.com 11 TH08 datasheet 4.2. Hysteresis The moisture absorbent film (polymeric dielectric) of the humidity sensor will carry a memory of its exposure history, particularly its recent or extreme exposure history. A sensor exposed to relatively low humidity will carry a negative offset relative to the factory calibration, and a sensor exposed to relatively high humidity will carry a positive offset relative to the factory calibration. This factor causes a hysteresis effect illustrated by the solid trace in Figure 6. The hysteresis value is the difference in %RH between the maximum absolute error on the decreasing humidity ramp and the maximum absolute error on the increasing humidity ramp at a single relative humidity setpoint and is expressed as a bipolar quantity relative to the average error (dashed trace). In the example of Figure 6, the measurement uncertainty due to the hysteresis effect is ±1.0%RH. 4.3. Prolonged Exposure to High Humidity Prolonged exposure to high humidity will result in a gradual upward drift of the RH reading. The shift in sensor reading resulting from this drift will generally disappear slowly under normal ambient conditions. The amount of shift is proportional to the magnitude of relative humidity and the length of exposure. In the case of lengthy exposure to high humidity, some of the resulting shift may persist indefinitely under typical conditions. It is generally possible to substantially reverse this affect by baking the device (see section “4.6. Bake/Hydrate Procedure” ). 4.4. PCB Assembly 4.4.1. Soldering Like most ICs, TH08 devices are shipped from the factory vacuum-packed with an enclosed desiccant to avoid any RH accuracy drift during storage and to prevent any moisture-related issues during solder reflow. The following guidelines should be observed during PCB assembly:  TH08 devices are compatible with standard board assembly processes. Devices should be soldered using reflow per the recommended card reflow profile. See Section “10. PCB Land Pattern and Solder Mask Design” for the recommended card reflow profile.  A "no clean" solder process is recommended to minimize the need for water or solvent rinses after soldering. Cleaning after soldering is possible, but must be done carefully to avoid impacting the performance of the sensor.  It is essential that the exposed polymer sensing film be kept clean and undamaged. This can be accomplished by careful handling and a clean, well-controlled assembly process. When in doubt or for extra protection, a heat-resistant, protective cover such as Kapton™ KPPD -1/8 polyimide tape can be installed during PCB assembly. TH08 may be ordered with a factory-fitted, solder-resistant protective cover. This cover provides protection during PCB assembly or rework but wiTH0ut the time and effort required to install and remove the Kapton tape. It can be left in place for the lifetime of the product, preventing liquids, dust or other contaminants from coming into contact with the polymer sensor film. See Section “8. Ordering Guide” for a list of ordering part numbers that include the cover. 4.4.2. Rehydration The measured humidity value will generally shift slightly after solder reflow. A portion of this shift is permanent and is accounted for in the accuracy specifications in Table 4. After soldering, an TH08 should be allowed to equilibrate under controlled RH conditions (room temperature, 45–55%RH) for at least 48 hours to eliminate the remainder of the shift and return the device to its specified accuracy performance.

membrane providing up to IP67 compliant protection. Table 8. Specifications of Protective Cover Following this cycle, the sensor will return to normal operation in typical ambient conditions after a few days.

Table 9. I2C Slave Address Byte Table 10. I2C Command Table code determines which mode is used. checksum byte is calculated using a CRC generator polynomial of x8 + x5 + x4 + 1, with an initialization of 0x00. 0xE3, and 0xF3. For all other commands, the checksum byte is not supported.

Tel:+86-755-82973805 Fax: +86-755-82973550 Email:sales@hoperf.com http://www.hoperf.com 14 TH08 datasheet Sequence to perform a measurement and read back result(Hold Master Mode) *Note: Device will NACK the slave address byte until conversion is complete

Tel:+86-755-82973805 Fax: +86-755-82973550 Email:sales@hoperf.com http://www.hoperf.com 15 ---- S 5.1.1. Measuring Relative Humidity Once a relative humidity measurement has been made, the results of the measurement may be converted to percent relative humidity by using the following expression: – 6 65536 Where: %RH is the measured relative humidity value in %RH RH_Code is the 16-bit word returned by the TH08 A humidity measurement will always return XXXXXX10 in the LSB field. Due to normal variations in RH accuracy of the device as described in Table 4, it is possible for the measured value of %RH to be slightly less than 0 when the actual RH level is close to or equal to 0. Similarly, the measured value of %RH may be slightly greater than 100 when the actual RH level is close to or equal to 100. This is expected behavior, and it is acceptable to limit the range of RH results to 0 to 100%RH in the host software by truncating values that are slightly outside of this range. 5.1.2. Measuring Temperature Each time a relative humidity measurement is made a temperature measurement is also made for the purposes of temperature compensation of the relative humidity measurement. If the temperature value is required, it can be read using command 0xE0; this avoids having to per form a second temperature measurement. The measure temperature commands 0xE3 and 0xF3 will perform a temperature measurement and return the measurement value, command 0xE0 does not perform a measurement but returns the temperature value measured during the relative humidity measurement. The checksum output is not available with the 0xE0 command. Sequence to read temperature value from previous RH measurement Slave Address W A 0xE0 A Sr Slave Address R A MS Byte A LS Byte NA P

Tel:+86-755-82973805 Fax: +86-755-82973550 Email:sales@hoperf.com http://www.hoperf.com 20 ---- The results of the temperature measurement may be converted to temperature in degrees Celsius (°C) using the following expression: 65536 Where: Temperature (°C) is the measured temperature value in °C Temp_Code is the 16-bit word returned by the TH08 A temperature measurement will always return XXXXXX00 in the LSB field.

Tel:+86-755-82973805 Fax: +86-755-82973550 Email:sales@hoperf.com http://www.hoperf.com 21 5.2. Reading and Writing User Registers There is one user register on the TH08 that allows the user to set the configuration of the TH08. The procedure for accessing that register is described below. The checksum byte is not supported after reading a user register. Slave S W A Address Read Reg Cmd Sequence to read a register Slave A Sr Address R A Read Data NA P Sequence to write a register S Slave Address W A Write Reg Cmd A Write Data A P 5.3. Firmware Revision The internal firmware revision can be read with the following I2C transaction: Slave S Address W A 0x84 A 0xB8 A S Slave Address R A FWREV A NA P The values in this field are encoded as follows: 0xFF=Firmware version 1.0 5.4. Heater The TH08 contains an integrated resistive heating element that may be used to raise the temperature of the sensor. This element can be used to test the sensor, to drive off condensation, or to implement dew-point measurement when the TH08 is used in conjunction with a separate temperature sensor such as another TH08 (the heater will raise the temperature of the internal temperature sensor). The heater can be activated using HTRE, bit 2 in User Register 1. Turning on the heater will reduce the tendency of the humidity sensor to accumulate an offset due to "memory" of sustained high humidity conditions.

Table 11. Register Summary

  1. Any register not listed here is reserved and must not be written. The result of a read operation on these bits is
  2. Except where noted, reserved register bits will always read back as “1,” and are not affected by write operations. For

from the RSVD bits should be written back unchanged during the write operation. device will no longer operate correctly.

Tel:+86-755-82973805 Fax: +86-755-82973550 Email:sales@hoperf.com http://www.hoperf.com 23 7. Pin Descriptions Pin Name Pin # Pin Description VDD 1 Power. This pin is connected to power on the circuit board. SDA 2 I2C data SCL 3 I2C clock GND 4 Ground. This pin is connected to ground on the circuit board through a trace. Do not connect directly to GND plane.

Tel:+86-755-82973805 Fax: +86-755-82973550 Email:sales@hoperf.com http://www.hoperf.com 24 8. Package Outline Dimension Min Nom Max A 2.6 2.7 2.8 B 8.0 8.1 8.2 C 1.7 1.8 1.9 D 10.8 E 9.1 F ∮0.7 ∮0..8 ∮0.9 G 1.6 1.8 2.0 H 1.7 1.8 1.9 I 0.7 0.8 0.9 Notes: 1. All dimensions are shown in millimeters (mm).

Tel:+86-755-82973805 Fax: +86-755-82973550 Email:sales@hoperf.com http://www.hoperf.com 25 HOPE MICROELECTRONICS CO.,LTD Add: 2/F, Building 3, Pingshan Private Enterprise Science and Technology Park, Lishan Road, XiLi Town, Nanshan District, Shenzhen, Guangdong, China Tel: 86-755-82973805 Fax: 86-755-82973550 Email: sales@hoperf.com Website: http://www.hoperf.com http://www.hoperf.cn This document may contain preliminary information and is subject to change by Hope Microelectronics wiTH0ut notice. Hope Microelectronics assumes no responsibility or liability for any use of the information contained herein. Nothing in this document shall operate as an express or implied license or indemnity under the intellectual property rights of Hope Microelectronics or third parties. The products described in this document are not intended for use in implantation or other direct life support applications where malfunction may result in the direct physical harm or injury to persons. NO WARRANTIES OF ANY KIND, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MECHANTABILITY OR FITNESS FOR A ARTICULAR PURPOSE, ARE OFFERED IN THIS DOCUMENT. ©2006, HOPE MICROELECTRONICS CO.,LTD. All rights reserved.