ATH25 Data Sheet

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Version:V1.0 —— May 2021

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Do not use the sensor in corrosive gas or condensed water.

4.2 Storage Conditions and Operating Instructions

The level of the humidity sensitivity (MSL) is 1, according to the IPC/JEDEC J-STD-020

standard. Therefore, it is recommended to use it within one year after shipment.

This kind of the sensor is not an ordinary electronic component and needs to be carefully

protected. Users must pay more attention to this key point. Long-term exposure to high

concentrations of chemical vapor will cause the output signal of the sensor drift. Therefore, it is

recommended to store the sensor in the original packaging including a sealed ESD bag, and

meet the following conditions: temperature range 10℃ - 50℃ (a limited time within 0-85℃ );

humidity 20-60%RH (the sensor without ESD package). For those sensors which had been

removed from the original packaging, we recommend to store them in an antistatic bag made

of PET/AL/CPE containing metal.

During production and transportation, the sensor should be avoided to contact with high

concentrations of chemical solvents and long-term exposure in the air. It is should to avoid to

contact with volatile glues, tapes, stickers or volatile packaging materials, such as foam foils

and foam materials, etc. The area of production should be well ventilated.

4.3 Recovery Processing

As mentioned above, if the sensor had been exposed to extreme working conditions or

chemical vapors, the output signal will drift. It can be restored to the calibration state by the

following processing.

Drying: Keep for 6 hours under 60-65℃ and <5%RH humidity conditions;

Rehydration: Keep for 6 hours under 20-30℃ and >75%RH humidity conditions7.

4.4 Temperature Effect

The relative humidity of the gas depends to a large extent on the temperature. Therefore, it is

necessary to ensure that all sensors measuring the same humidity operate at the same

condition of temperature. It should to make sure that the tested sensor and the reference

sensor are at the same conditions when operate the test, and then compare the output signals.

In addition, when the measurement is at high frequency, the temperature of the sensor will rise,

so it will affect the accuracy. If you want to ensure the variation of the temperature of the

sensor is less than 0.1°C, the activation time of ATH25 should not exceed 10% of the

measurement time. It is recommended to measure the data every 2 seconds.

4.5 Materials for Sealing and Encapsulation

Many materials can absorb moisture and will act as a buffer, which will increase the time of

response and lag. Therefore, the materials around the sensors should be carefully selected.

The recommended materials are: metal materials, LCP, POM(Delrin), PTFE(Teflon), PE, PEEK,

PP, PB, PPS, PSU, PVDF, PVF.

Material used for sealing and bonding (conservative recommendation): It is recommended to

use epoxy resin or silicone resin to encapsulate electronic components. The gases released by

these materials may also contaminate ATH25 (see 4.2). Therefore, the sensor should be

assembled last, and stored in a well-ventilated place, or dried for 24 hours in an environment

of >50℃ , so as to release the polluted gas before packaging.

4.6 Wiring Rules and Signal Integrity

If the signal lines of SCL and SDA are parallel and very close to each other, it may cause signal

crosstalk and communication failure. The solution is to place VDD and/or GND between the two

signal lines, separate the signal lines, and use shielded cables. In addition, reduce SCL

frequency may also improve the integrity of signal transmission. This capacitor should be as

close as possible to the sensor. See the next chapter.