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Version:V1.0 —— May 2021

AHT20 Data Sheet

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Figure 9. JEDEC Standard welding procedure diagram. Tp<=260°C，tp<30 sec, lead-free welding. TL<220°C，tl<150 sec,

The rate of temperature rise and fall during welding shall be < 5°C/sec

Sensor can be welded through standard reflow furnace. The sensor fully meets the IPC/JEDEC J-STD-020D

welding standard. The contact time should be less than 30 seconds at the highest 260℃ (see Fig. 9) and the

ultimate welding temperature that the sensor can withstand is 260℃，so it is recommended to use low

temperature 180℃ when reflow soldering.

Note: After reflow welding, the sensor should be stored at room temperature of 25℃ and relative humidity greater

than 75%RH for 12~72 hours, or placed at temperature of 60℃~85℃ and relative humidity greater than 85%RH

for 2~6 hours, to ensure the rehydration of the polymer , otherwise it will lead to sensor reading drift. Using low

temperature reflow (e.g.180℃) can reduce hydration time.

Don't not use the sensor in corrosive gas or condensed water.

4..2 Storage Conditions and Operating Instructions

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

recommended to use it within one year after shipment.

The temperature and humidity sensor is not an ordinary electronic component and needs to be carefully protected.

Users must pay attention to this point. Long-term exposure to high concentrations of chemical vapor will cause the

sensor's readings to 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℃ (within a limited time 0-85℃);

humidity 20-60%RH (without ESD package) sensor). For those sensors that have been removed from the original

packaging, we recommend storing them in an antistatic bag made of PET/AL/CPE containing metal.

During production and transportation, the sensor should avoid contact with high concentrations of chemical

solvents and long-term exposure. Avoid contact with volatile glues, tapes, stickers or volatile packaging materials,

such as foam foils and foam materials Wait. The production area should be well ventilated.

4.3 Recovery Processing

As mentioned above, the readings can drift if the sensor is exposed to extreme operating conditions or chemical

vapors. It can be restored to the calibration state by the following processing. If the humidity is high, take drying

measures: keep it at 60-85℃ and <5%RH for 2-10 hours until recovery; If the humidity is low, it can be rehydrated.

Refer to Section 4.1 for reflow soldering after rehydration treatment.

4.4 Temperature Effect

The relative humidity of gases depends largely on temperature. Therefore, when measuring humidity, all sensors

measuring the same humidity should work at the same temperature as possible. When testing, it is necessary to

ensure that the same temperature, and then compare the humidity readings.

If the sensor and the heating-prone electronic components are placed on the same printing circuit board, measures