www.sensirion.com / D1

Version 2

– July 2021

8/17

Parameter

Symbol

Conditions

Min.

Typ.

Max.

Units

Comments

Power-up time

tPU

After hard reset,

VDD

≥ VPOR

-

0.3

1

ms

Time between VDD

reaching VPOR and

sensor entering idle

state

Soft reset time

tSR

After soft reset

-

-

1

ms

Time between ACK of

soft reset command and

sensor entering idle

state. Also valid for I2C

general call reset.

Measurement

duration

tMEAS,l

Low

repeatability

-

1.3

1.7

ms

The three repeatability

modes differ with

respect to measurement

duration, noise level and

energy consumption

tMEAS,m

Med.

repeatability

-

3.7

4.5

ms

tMEAS,h

High

repeatability

-

6.9

8.2

ms

Heater-on duration

tHeater

Long pulse

0.9

1

1.1

s

After that time the heater

is automatically switched

off

Short pulse

0.09

0.1

0.11

s

After that time the heater

is automatically switched

off

Table 4 System timing specifications.

3.3 Absolute Maximum Ratings

Stress levels beyond those listed in Table 5 may cause permanent damage or affect the reliability

of the device. These are stress ratings only and functional operation of the device at these

conditions is not guaranteed. Ratings are only tested each at a time.

Parameter

Rating

Max. voltage on any pin

VSS -

0.3 V … VDD + 0.3 V

Operating temperature range

-40

°C … 125 °C

Storage temperature range11

-40

°C …150 °C

ESD HBM

2 kV

ESD CDM

500 V

Latch up, JESD78 Class II, 125°C

+-100 mA

Table 5: Absolute maximum ratings.

4 Sensor Operation

4.1 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 and 8-bit checksum (cyclic redundancy check = CRC). 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. The sensor does not support clock-

stretching. In case the sensor receives a read header and is still busy with e.g. measurement or

11 The recommended storage temperature range is 10-50°C. Please consult the document “SHTxx Handling Instructions” for more information.