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Parameter

Rating

Supply voltage VDD

-0.3 V … 6.0 V

Max. voltage on any pin

VSS -0.3 V … VDD +0.3 V

Operating temperature range

-40 °C … 125 °C

Storage temperature range9

-40 °C …150 °C

ESD HBM

6 kV

ESD CDM

750 V

Latch up, JESD78 Class II, 125°C

±100 mA

Table 7. Absolute maximum ratings.

5

Sensor Operation

5.1 I2C Communication

I2C communication is based on NXP’s I2C-bus specification and user manual UM10204, Rev.6, 4 April 2014.

Supported I2C modes are standard, fast mode, and fast mode plus. Data is transferred in multiples of 16-bit

words. In order to increase reliability of data transfer, I2C glitch protection is offered in form of 8-bit checksum

(cyclic redundancy check = CRC, see section 4.4). All transfers must begin with a start condition (S) and

terminate with a stop condition (P). To finish a read transfer, send not acknowledge (NACK) and stop condition

(P). Addressing a specific slave device is done by sending its 7-bit I2C address followed by an eighth bit,

denoting the communication direction: “zero” indicates transmission to the slave, i.e. “write”, a “one” indicates

a “read” request. Schematics of the I2C transfer types are sketched in Figure 8.

Figure 5. I2C transfer types: First a write header is sent to the I2C slave, followed by a command, for example

“measure RH&T with highest precision”. After the measurement is finished the read request directed to this

I2C slave will be acknowledged and transmission of data will be started by the slave.

5.1.1 I2C Communication Timing

All details on the timing are following the interface specification of NXP’s user manual UM10204, Rev.6, 4 April

2014. Please follow mandatory capacitor and resistor requirements given in Table 3.

5.2 I2C Data type & length

I2C bus operates with 8-bit data packages. Information from the sensor to the master has a checksum after

every second 8-bit data package.

Humidity and temperature data will always be transmitted in the following way: The first value is the

temperature signal (2 * 8-bit data + 8-bit CRC), the second is the humidity signal (2 * 8-bit data + 8-bit CRC).

9

The recommended storage temperature range is 10-50 °C. Please consult (Sensirion, Handling Instructions for Humidity Sensors, 2020

[1]) for more information.