www.sensirion.com / D1

Version 7.1 – March 2025

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Possible Heater Use Cases

There will be dedicated Sensirion application notes elaborating on various use cases of the heater. In general,

the applications of the on-package heater range around:

1.

Removal of condensed / spray water on the sensor surface. Although condensed water is not a

reliability / quality problem to the sensor, it will however make the sensor non-responsive to RH

changes in the air as long as there is liquid water on the surface.

2.

Creep-free operation in high humid environments. Periodic heating pulses allow for creep-free

high-humidity measurements for extended times.

Important notes for operating the heater:

1.

The heater is designed for a maximum duty cycle of 10%, meaning the total heater-on-time

should not be longer than 10% of the sensor’s lifetime.

2.

During operation of the heater, sensor specifications are not valid.

3.

The temperature sensor can additionally be affected by the thermally induced mechanical stress,

offsetting the temperature reading from the actual temperature.

4.

The sensor’s temperature (base temperature + temperature increase from heater) must not

exceed Tmax = 125 °C in order to have proper electrical functionality of the chip.

5.

The heater draws a large amount of current once enabled (up to ~75 mA in the highest power

setting). Although a dedicated circuitry draws this current smoothly, the power supply must be

strong enough to avoid large voltage drops that could provoke a sensor reset.

6.

If higher heating temperatures are desired, consecutive heating commands must be sent to the

sensor. The heater shall only be operated in ambient temperatures below 65 °C or else it could

drive the sensor outside of its maximal operating temperature.