NSHT35

Humidity and Temperature Sensor with

SMBus and I

C Interface

Datasheet (EN) 0.2

Page 1

Product Overview

NSHT35 is the temperature and humidity sensors with

SMBus and I

C interface. It builds on a CMOS-MEMS

sensor chip that is at the heart of Novosense’s new

humidity and temperature platform. NSHT35 providing

high accuracy measurements with very low power

consumption in a small DFN and LGA package. The DFN

and LGA package has a footprint of 2.5 x 2.5 mm

while

keeping a height of 0.9 mm. This allows for integration of

the NSHT35 into a great variety of applications. Its

functionality includes enhanced signal processing, two

distinctive and user selectable I

C addresses and

communication speeds of up to 1 MHz. Additionally, the

wide supply voltage range of 1.8 V to 5.5 V guarantees

compatibility with diverse assembly situations. The

capacitive-based sensor includes new integrated digital

features and a heating element to dissipate condensation

and moisture. The NSHT35 digital features include

programmable interrupt thresholds to provide alerts and

system wake-ups without requiring a microcontroller to

continuously monitor the system.

Key Features

 Fully calibrated, linearized, and temperature

compensated digital output

 Wide supply voltage range, from 1.8 V to 5.5 V

 I

C Interface with communication speeds up to 1 MHz

and two user selectable addresses

 Typical accuracy of 3 %RH and 0.3 °C for NSHT35

 Very fast start-up and measurement time

 Tiny 8-Pin DFN and LGA package

Applications

 HVAC

 Smart Thermostats and Room Monitors

 White Goods

 Printers

 Handheld Meters

 Medical Devices

 Wireless Sensor

Device Information

Part Number

Package

Body Size

NSHT30-DDNR

DFN (8)

2.5mm × 2.5mm

NSHT30-CLAR

LGA (8)

2.5mm × 2.5mm

Typical Application

nRESETALERT

ADDR

GND

VDD

SCL

SDA

Die

pad

100nF

VDD

NSHT35

Datasheet (EN) 0.2

Page 2

Index

PIN CONFIGURATION AND FUNCTIONS ................................................................................................................................................................ 3

1.0 ABSOLUTE MAXIMUM RATINGS ..................................................................................................................................................................... 4

2.0 ELECTRICAL CHARACTERISTICS ....................................................................................................................................................................... 4

2.1 ELECTRICAL CHARACTERISTICS ............................................................................................................................................................................. 4

2.2 TIMING SPECIFICATION FOR THE SENSOR SYSTEM .................................................................................................................................................... 5

2.3 I

C TIMING DIAGRAM ....................................................................................................................................................................................... 5

2.4 I

C TIMING CHARACTERISTICS .............................................................................................................................................................................. 5

3.0 SENSOR PERFORMANCE ................................................................................................................................................................................. 7

3.1 HUMIDITY SENSOR SPECIFICATION ........................................................................................................................................................................ 7

3.2 TEMPERATURE SENSOR SPECIFICATION .................................................................................................................................................................. 7

4.0 PIN ASSIGNMENT ............................................................................................................................................................................................ 8

4.1 POWER PINS ................................................................................................................................................................................................... 8

4.2 SERIAL CLOCK AND SERIAL DATA (SCL, SDA) ......................................................................................................................................................... 8

4.3 DIE PAD (CENTER PAD) ...................................................................................................................................................................................... 8

4.4 ADDR PIN ..................................................................................................................................................................................................... 8

4.5 ALERT PIN..................................................................................................................................................................................................... 9

4.6 NRESET PIN ................................................................................................................................................................................................... 9

5.0 OPERATION AND COMMUNICATION ............................................................................................................................................................ 10

5.1 POWER-UP AND COMMUNICATION START ........................................................................................................................................................... 10

5.2 STARTING A MEASUREMENT ............................................................................................................................................................................. 10

5.3 MEASUREMENT COMMANDS FOR SINGLE SHOT DATA ACQUISITION MODE ................................................................................................................. 10

5.4 READOUT OF MEASUREMENT RESULTS FOR SINGLE SHOT MODE ............................................................................................................................... 11

5.5 MEASUREMENT COMMANDS FOR PERIODIC DATA ACQUISITION MODE ...................................................................................................................... 12

5.6 READOUT OF MEASUREMENT RESULTS FOR PERIODIC MODE .................................................................................................................................... 12

5.7 ART COMMAND ............................................................................................................................................................................................ 13

5.8 BREAK COMMAND / STOP PERIODIC DATA ACQUISITION MODE ................................................................................................................................ 13

5.9 RESET .......................................................................................................................................................................................................... 13

5.10 HEATER ...................................................................................................................................................................................................... 14

5.11 STATUS REGISTER ......................................................................................................................................................................................... 15

5.12 CHECKSUM CALCULATION ............................................................................................................................................................................... 16

5.13 CONVERSION OF SIGNAL OUTPUT ..................................................................................................................................................................... 16

6.0 ACTIVATION AND DEACTIVATION OF THE ALERT MODE ............................................................................................................................... 17

6.1 ACTIVATION AND DEACTIVATION OF THE ALERT MODE ............................................................................................................................................ 17

6.2 ALERT MODE LIMITS ....................................................................................................................................................................................... 17

6.2.1 Data Format for the Alert Limits ........................................................................................................................................................ 17

6.2.2 Standard values for the Alert Limits .................................................................................................................................................. 18

6.2.3 Alert Mode Commands ..................................................................................................................................................................... 18

6.2.4 Typical procedure to calculate the limits ........................................................................................................................................... 19

6.2.5 Typical procedure to change the alert condition ............................................................................................................................... 19

6.3 FURTHER CONDITION THAT CAN RAISE AN ALERT ..................................................................................................................................................... 19

7.0 PACKAGE INFORMATION ............................................................................................................................................................................... 20

7.1 DFN (8) PACKAGE .......................................................................................................................................................................................... 20

7.2 LGA (8) PACKAGE .......................................................................................................................................................................................... 21

8.0 ORDER INFORMATION .................................................................................................................................................................................. 22

9.0 REVISION HISTORY ........................................................................................................................................................................................ 23