HDC3020 [TI]
HDC302x High-Accuracy, Low-Power, Digital Humidity and Temperature Sensor With Ultra-Low Drift;型号: | HDC3020 |
厂家: | TEXAS INSTRUMENTS |
描述: | HDC302x High-Accuracy, Low-Power, Digital Humidity and Temperature Sensor With Ultra-Low Drift |
文件: | 总51页 (文件大小:2002K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
HDC3020
SNAS778 – JUNE 2021
HDC302x High-Accuracy, Low-Power, Digital Humidity and Temperature Sensor With
Ultra-Low Drift
1 Features
3 Description
•
Relative humidity (RH) sensor:
– Operating range: 0% to 100%
– Accuracy: ±1.5% typical
– Drift Correction: reduces offset to return device
to within accuracy specification
– Long-term drift: 0.21%RH/yr
– Condensation protection with integrated heater
Temperature sensor:
– Operating range: -40°C to 125°C
– Accuracy: ±0.1°C typical
NIST traceability: Relative humidity & temperature
Low power: average current 0.7 µA
I2C interface compatibility up to 1-Mhz speeds
– Four selectable I2C addresses
– Command/data protection through CRC
checksum
The HDC302x is an integrated capacitive based
relative humidity (RH) and temperature sensor, which
provides high accuracy measurements over a wide
supply range (1.62 V – 5.5 V), along with ultra-low
power consumption in a compact 2.5-mm × 2.5-mm
package. Both the temperature and humidity sensors
are 100% tested and trimmed on a production setup
that is NIST traceable and verified with equipment that
is calibrated to ISO/IEC 17025 standards.
•
Drift Correction reduces RH sensor offset due to
aging, exposure to extreme operating conditions, and
contaminants to return device to within accuracy
specifications. For battery IoT applications, auto
measurement mode and ALERT feature enable low
system power by maximizing MCU sleep time. There
are four different I2C addresses that support speeds
up to 1 MHz. A heating element is available to
dissipate condensation and moisture.
•
•
•
•
•
•
•
•
•
Supply voltage: 1.62 V to 5.50 V
Available auto measurement mode
Programmable interrupts
Programmable measurement calibration
Factory-installed polyimide tape assembly cover
Factory-installed IP67 rated environmental cover
The HDC3020 comes in an open cavity package
without a protective cover. Two device variants have
a cover option to protect the open cavity RH sensor:
HDC3021 and HDC3022. HDC3021 has removable
protective tape to allow conformal coatings and
PCB wash. HDC3022 has a permanent IP67 filter
membrane cover to protect against dust and water.
2 Applications
•
•
•
•
•
•
•
•
•
•
•
Washer & dryer
Refrigerator & freezer
Industrial transport
Cold Chain asset tracking & data logger
IoT environmental sensors
Air quality and gas detection
Humidifier/dehumidifier
Thermostat
CPAP and ventilator
Water leak detector
IP Camera
Device Information
PART NUMBER
PACKAGE(1)
BODY SIZE (NOM)
HDC3020
HDC3021(2)
HDC3022(2)
WSON (8)
2.50 mm × 2.50 mm
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
(2) Preview only.
3.30 V
HDC3
VDD
VDD
SCL
SDA
I2C
Controller
Calibration
ADC
ALERT
ADDR
ADDR1
I2C
GPIO
RH Sensor
T Sensor
Linearization
µC
RESET
GND
GND
Typical Application
Typical RH Accuracy vs. RH Setpoint (TA = 25°C)
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. ADVANCE INFORMATION for preproduction products; subject to change
without notice.
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Table of Contents
1 Features............................................................................1
2 Applications.....................................................................1
3 Description.......................................................................1
4 Revision History.............................................................. 2
5 Pin Configuration and Functions...................................3
6 Specifications.................................................................. 4
6.1 Absolute Maximum Ratings ....................................... 4
6.2 ESD Ratings .............................................................. 4
6.3 Recommended Operating Conditions ........................4
6.4 Thermal Information ...................................................4
6.5 Electrical Characteristics ............................................5
6.6 Switching Characteristics ...........................................7
6.7 Timing Diagram...........................................................7
6.8 Typical Characteristics................................................8
7 Detailed Description........................................................9
7.1 Overview.....................................................................9
7.2 Functional Block Diagram...........................................9
7.3 Feature Description.....................................................9
7.4 Device Functional Modes..........................................12
7.5 Programming............................................................ 12
8 Application and Implementation..................................29
8.1 Application Information............................................. 29
8.2 Typical Application.................................................... 29
9 Power Supply Recommendations................................32
10 Layout...........................................................................32
10.1 Layout Guidelines................................................... 32
10.2 Layout Example...................................................... 33
10.3 Storage and PCB Assembly................................... 33
11 Device and Documentation Support..........................35
11.1 Documentation Support.......................................... 35
11.2 Receiving Notification of Documentation Updates..35
11.3 Support Resources................................................. 35
11.4 Trademarks............................................................. 35
11.5 Electrostatic Discharge Caution..............................35
11.6 Glossary..................................................................35
12 Mechanical, Packaging, and Orderable
Information.................................................................... 35
12.1 Package Option Addendum....................................45
12.2 Tape and Reel Information......................................47
4 Revision History
DATE
VERSION
NOTES
June 2021
*
Initial release.
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5 Pin Configuration and Functions
SDA
ADDR
ALERT
SCL
1
2
3
4
8
7
6
5
GND
ADDR1
RESET
V
DD
Not to scale
1. DEF package has a transparent top.
2. HDC3021 DEH and HDC3022 DEJ packages are preview only.
Figure 5-1. HDC302x DEF, DEH, or DEJ Package 8-Pin WSON Top View
Table 5-1. Pin Functions
PIN
TYPE(1)
DESCRIPTION
NAME
VDD
NO.
5
P
G
I
Supply Voltage. From 1.62 V to 5.50 V.
Ground
GND
SCL
8
4
Serial clock line for I2C, open-drain; requires a pullup resistor to VDD
.
SDA
1
I/O
Serial data line for I2C, open-drain; requires a pullup resistor to VDD
I2C Device Address Pin.
.
For device addresses 0x44 and 0x45, ADDR1 voltage must be below maximum VIL or left floating.
0x44 requires ADDR voltage to be below maximum VIL or left floating.
0x45 requires ADDR voltage to be above minimum VIH.
ADDR
2
7
I
I
I2C Device Address Pin.
For device addresses 0x46 and 0x47, ADDR1 voltage must be above minimum VIH.
0x46 requires ADDR voltage to be below maximum VIL or left floating.
0x47 requires ADDR voltage to be above minimum VIH.
ADDR1
RESET
ALERT
6
3
I
Reset Pin. Active Low. If not used, leave floating or tie to VDD.
Interrupt Pin to drive high impedance loads. Push-Pull Output.
If not used, must be left floating.
O
(1) Type:
G = Ground
I = Input
O = Output
P = Power
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6 Specifications
6.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted)(1)
MIN
–0.3
–0.3
–0.3
–0.3
–0.3
–0.3
–0.3
–55
MAX
6.0
UNIT
V
VDD
Applied Voltage on VDD pin
Applied Voltage on SCL pin
Applied Voltage on SDA pin
Applied Voltage on ADDR pin
Applied Voltage on ADDR1 pin
Applied Voltage on ALERT pin
Applied Voltage on RESET pin
Junction temperature
SCL
6.0
V
SDA
6.0
V
ADDR
ADDR1
ALERT
RESET
TJ
6.0
V
VDD + 0.3
VDD + 0.3
VDD + 0.3
150
V
V
V
°C
°C
Tstg
Storage temperature
–65
150
(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress
ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under
Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device
reliability.
6.2 ESD Ratings
VALUE
UNIT
Human body model (HBM), per ANSI/ESDA/JEDEC
±2000
JS-001(1)
Charged device model (CDM), per JEDEC specification
V(ESD)
Electrostatic discharge
All Pins
±500
±750
V
JESD22-C101(2)
Charged device model (CDM), per JEDEC specification
JESD22-C101(2)
Corner Pins
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process
(2) JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process
6.3 Recommended Operating Conditions
PARAMETER
MIN
1.62
–40
–20
–40
0
MAX UNIT
VDD
Supply voltage
5.5
125
70
V
TTEMP
TRH
Temperature Sensor - Operating free-air temperature
°C
°C
°C
Relative Humidity Sensor - Operating free-air temperature
Integrated Heater for condensation removal - Operating free-air temperature(1)
Relative Humidity Sensor Operating Range (Non-condensing) (1)
THEATER
RHOR
60
100 %RH
(1) Prolonged operation outside the recommended temperature operating conditions and/or at >80%RH with temperature in the higher
recommended operating range can result in a shift of sensor reading, with slow recovery time. See Exposure to High Temperature and
High Humidity Conditions for more details.
6.4 Thermal Information
HDC3x
THERMAL METRIC(1)
DEF, DEH, and DEJ
UNIT
8 PINS
84.9
N/A
RθJA
Junction-to-ambient thermal resistance
Junction-to-case (top) thermal resistance(2)
Junction-to-board thermal resistance
°C/W
°C/W
°C/W
°C/W
RθJC(top)
RθJB
52.0
N/A
ΨJT
Junction-to-top characterization parameter(2)
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HDC3x
DEF, DEH, and DEJ
8 PINS
THERMAL METRIC(1)
UNIT
ΨJB
Junction-to-board characterization parameter
Junction-to-case (bottom) thermal resistance
51.7
°C/W
°C/W
RθJC(bot)
30.4
(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application
report.
(2) JEDEC standard JESD51-X specifies this measurement at the center position on the top surface of the package. Due to the location of
the cavity opening at the center position, this measurement is not applicable.
6.5 Electrical Characteristics
TA = -40°C to 125°C, VDD = 1.62V to 5.50V (unless otherwise noted), Typical Specifications are TA = 25°C, VDD
=
1.8V unless otherwise noted
PARAMETER
Current Consumption
TEST CONDITIONS
MIN
TYP
MAX
UNIT
Low Power Mode 0 (lowest noise)
Low Power Mode 1
125
TBD
TBD
100
TBD
IDD_ACTIVE Active Current(1)
µA
Low Power Mode 2
Low Power Mode 3
TBD
TBD
No Active Measurement
trigger on demand mode
0.4
IDD_SLEEP Sleep Current(1)
µA
No Active Measurement,
auto measurement mode
0.55
TBD
IDD_AVG_E
measurement freq = numbers of samples per
second
(9)
Averaged Current Equation
QN
Low Power Mode 0 (lowest noise)
Averaged at 1 sample per second
2.0
1.2
1.0
0.9
0.7
30
TBD
TBD
TBD
TBD
TBD
TBD
Low Power Mode 1
Averaged at 1 sample per second
Low Power Mode 2
Averaged at 1 sample per second
IDD_AVG
Averaged Current(1) (2)
µA
Low Power Mode 3 (lowest power)
Averaged at 1 sample per second
Low Power Mode 3 (lowest power)
Averaged at 1 sample every two seconds
Heater Current (Condensation
Removal)
THEATER - TAMBIENT = 20°C. VDD = 3.3V for
Typical Value
IHEATER
mA
Sensor Timing
Low Power Mode 0 (lowest noise)
Low Power Mode 1
12.0
7.0
4.5
3.3
TBD
TBD
TBD
TBD
tmeas
Measurement Duration (8)
ms
ms
ms
Low Power Mode 2
Low Power Mode 3 (lowest power)
Sensor ready once VDD ≥ 1.62V
TA = 25°C
0.5
1
SensorPU
Power Up Ready
Soft Reset Ready
R
Sensor ready once VDD ≥ 1.62V
1.5
Sensor ready once Soft Rest Command
received
TA = 25°C
0.5
1
SensorSR
R
Sensor ready once Soft Rest Command
received
1.5
Relative Humidity Sensor
RHACC
Accuracy(3) (4)
TA = 25°C, 10% to 90% RH
±1.5
±2
%RH
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UNIT
SNAS778 – JUNE 2021
TA = -40°C to 125°C, VDD = 1.62V to 5.50V (unless otherwise noted), Typical Specifications are TA = 25°C, VDD
1.8V unless otherwise noted
=
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
at ambient room tempTA = 25°C, 10% to 90%
RH
Low Power Mode 0 (lowest noise)
±0.02
TA = 25°C, 10% to 90% RH
Low Power Mode 1
TBD
TBD
RHREP
Repeatability
%RH
TA = 25°C, 10% to 90% RH
Low Power Mode 2
TA = 25°C, 10% to 90% RH
Low Power Mode 3 (lowest power)
TBD
±1
RHHYS
RHRT
Hysteresis (5)
TA = 25°C, 10% to 90% RH
%RH
s
TA = 25°C, 10% to 90% RH
t63% step.
Response Time(6) (7)
Long-term Drift (4)
4
RHLTD
0.21
%RH/yr
Temperature Sensor
-20°C ≤ TA ≤ 60°C
±0.1
±0.2
±0.3
±0.4
TEMPACC Accuracy
°C
°C
-40°C ≤ TA < -20°C or 60°C < TA ≤ 125°C
Low Power Mode 0 (lowest noise)
Low Power Mode 1
±0.04
TBD
TEMPREP Repeatability
Low Power Mode 2
TBD
Low Power Mode 3 (lowest power)
±0.07
25C <TA< 75C
t63% step
TEMPRT Response Time (in air)(6) (7)
TBD
s
TEMPLTD Long Term Drift
±0.03
0.3*VDD
0.4
°C/yr
SCL, SDA Pins
VIL
LOW-level input voltage
HIGH-level input voltage
LOW-level output voltage
V
V
V
VIH
VOL
0.7*VDD
VDD–0.2
IOL = 3 mA
Control Pins
High-level Output Voltage -
VOH_ALERT
IOH = -100 µA
IOL = 100 µA
V
V
ALERT
Low-level Output Voltage -
ALERT
VOL_ALERT
0.2
VIH_ADDR High Level Input Voltage - ADDR
VIL_ADDR Low Level Input Voltage - ADDR
0.7*VDD
0.7*VDD
V
V
0.3*VDD
High Level Input Voltage -
VIH_ADDR1
ADDR1
V
V
V
VIL_ADDR1 Low Level Input Voltage - ADDR1
0.3*VDD
High Level Input Voltage -
VIH_RESET
RESET
0.7*VDD
VIL_RESET Low Level Input Voltage - RESET
0.3*VDD
V
II_ADDR
Input Leakage Current - ADDR
VI = VDD or GND
-1
-1
1
1
µA
µA
II_ADDR1
Input Leakage Current - ADDR1 VI = VDD or GND
EEPROM (T, RH offset)
OSEND
OSRET
Program Endurance
Data Retention Time
1000
10
50000
100
Cycles
Years
100% Power-On hours
(1) Does not include I2C read/write communication or pullup resistor current through SCL and SDA
(2) Average current consumption while conversion is in progress
(3) Excludes hysteresis and long-term drift
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(4) Based on THB (temperature humidity bias) testing. Excludes the impact of dust, gas phase solvents and other contaminents such as
vapors from packaging materials, adhesives, or taptes, etc.
(5) The hysteresis value is the difference between the RH measurement in a rising and falling RH environment, at a specific RH point
(6) Actual response times will vary dependent on system thermal mass and air-flow
(7) Time for the RH output to change by 63% of the total RH change after a step change in environmental humidity
(8) Measurement duration includes the time to measure RH plus Temp
(9) IDD_AVG_EQN = measuruement freq x IDD_ACTIVE x tmeas+ Isleep x (1- (measurement freq x tmeas))
6.6 Switching Characteristics
TA = -40°C to 125°C and VDD = 1.62V to 5.50V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP MAX UNIT
SCL, SDA PINS
fSCL
SCL clock frequency(1)
0
0.6
1.3
100
0
1
MHz
µs
tHIGH
High period of the SCL clock(1)
LOW period of the SCL clock(1)
Setup Time: Data(1)
tLOW
µs
tSU;DAT
tHD;DAT
tSU;STA
tHD;STA
tSU;STO
tR;SCL
ns
Hold Time: Data(1)
µs
Set-up time: Repeated START condition(1)
Hold time: Repeated START condition(1) (2)
Set-up time: STOP condition(1)
Rise Time: SCL(1)
0.6
0.6
0.6
µs
µs
µs
300 ns
300 ns
300 ns
300 ns
µs
tR;SDA
Rise Time: SDA(1)
tF;SCL
Fall Time: SCL(1)
20*(VDD/5.5V)
20*(VDD/5.5V)
1.3
tF;SDA
Fall Time: SDA(1)
tBUF
Bus free time between a STOP and START condition(1)
Data valid time(1) (3)
tVD;DAT
tVD;ACK
RESET
tRESET_NPW
0.9 µs
0.9 µs
Data valid acknowledge time(1) (4)
Negative pulse width to trigger hard reset
1
µs
EEPROM (T, RH OFFSET)
tOS_PROG
Offset Programming Time
10
15 ms
(1) Guaranteed by design/characterization; not production tested
(2) After this period, the first clock pulse is generated
(3) Time for data signal from SCL low to SDA output (high to low, depending on which is worse)
(4) Time for acknowledement signal from SCL low to SDA output (high or low, depending on which is worse)
6.7 Timing Diagram
tLOW
tR
tF
tHIGH
VIH
SCL
VIL
tSU;STO
tHD;DAT
tVD;DAT
tSU;STA
tHD;STA
tBUF
tSU;DAT
VIH
VIL
SDA
P
S
S
P
Figure 6-1. HDC302x I2C Timing Diagram
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6.8 Typical Characteristics
Unless otherwise noted. TA = 25°C, VDD = 1.80 V.
Graph Placeholder
Graph Placeholder
C00
C00
Figure 6-2. RH Accuracy vs. RH Set Point
Figure 6-3. T Accuracy vs. T Set Point
Graph Placeholder
C00
Figure 6-4. RH Accuracy vs. T Set Point
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7 Detailed Description
7.1 Overview
The HDC302x is an integrated digital interface sensor that incorporates both humidity-sensing and temperature-
sensing elements, an analog-to-digital converter, calibration memory, and an I2C compatible interface in a
2.50-mm × 2.50-mm, 8-pin WSON package. The HDC302x also provides excellent measurement accuracy.
The HDC302x measures relative humidity through variations in the capacitance of a polymer dielectric. As with
most relative humidity sensors that include this type of technology, care must be taken to ensure optimal device
performance for the sensing element. This includes:
•
Follow the correct storage and handling procedures during board assembly. See HDC3x Silicon User's Guide
(SNAU265) for these guidelines.
•
•
Protect the sensor from contaminants during board assembly and operation.
Reduce prolonged exposure to both high temperature and humidity extremes that may impact sensor
accuracy.
•
Follow the correct layout guidelines for best performance. See Optimizing Placement and Routing for
Humidity Sensors (SNAA297) for these guidelines.
7.2 Functional Block Diagram
HDC3
VDD
SCL
SDA
Calibration
ADC
ALERT
ADDR
ADDR1
Linearization
I2C
RH Sensor
T Sensor
RESET
GND
7.3 Feature Description
7.3.1 Factory Installed Polyimide Tape
The HDC3021 has a polyimide tape to cover the opening of the humidity sensor element. The tape protects the
humidity sensor element from pollutants that can be produced as part of the manufacturing process, such as
SMT assembly, printed circuit board (PCB) wash, and conformal coating. The tape must be removed after the
final stages of assembly for accurate measurement of relative humidity in the ambient environment. The tape
can withstand at least three standard reflow cycles.
To remove the polyimide tape from the humidity sensor element, TI recommends to use a ESD-safe tweezer to
grip the adhesive-free tab in the top right corner, and slowly peel the adhesive from the top-right corner towards
the bottom-left corner in an upward direction (as opposed to across the surface). This will help to reduce the risk
of scratching the humidity sensor element.
7.3.2 Factory Installed IP67 Protection Cover
HDC3022 has an IP67 rated PTFE permanent filter to cover the opening of the humidity sensor element. The
cover is a hydrophobic micropourous PTFE foil that protects the humidity sensor element against dust and water
according to IP67 specifications. The cover is designed to adhere to the package over lifetime operation while
maintaining the same response time as a sensor without the membrane. The cover has a filtration efficiency of
99.99% down to a particle size of 100 nm.
7.3.3 Measurement of Relative Humidity and Temperature
The HDC302x supports measurements of Relative Humidity and Temperature. The supported Relative Humidity
Range is 0% to 100% and the supported Temperature Range is from –40°C to 125°C. Each measurement is
represented in a 16-bit format, and the conversion formulas are documented below:
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(1)
(2)
(3)
7.3.4 Drift Correction: Accuracy Restoration
Due to contaminants, the natural aging of the sensor's polymer dielectric, and exposure to extreme operating
conditions resulting in long-term drift, the HDC302x offers drift correction to return the device to factory accuracy
specification. Drift correction is available on the EVM today with more details in the HDC3x EVM user's Guide
(SNAU267) and documentation for how to use this drift correction feature on individual devices without the EVM
will be added to the HDC3x Silicon User's Guide (SNAU265) before the device releases to production.
7.3.5 NIST Traceability of Relative Humidity and Temperature Sensor
The HDC302x units are 100% tested on a production setup that is NIST traceable and verified with equipment
that is calibrated to ISO/IEC 17025 accredited standards. This permits design of the HDC302x into applications
such as cold chain management, where the establishment of an unbroken chain of calibrations to known
references is essential.
7.3.6 Measurement Modes: Trigger-On Demand vs. Auto Measurement
Two types of measurement modes are available on the HDC302x: Trigger-on Demand and Auto Measurement
mode.
Trigger-on Demand is a single measurement reading of temperature and relative humidity that is triggered
through an I2C command on an as-needed basis. After the measurement is converted, the device remains in
sleep mode until another I2C command is received.
Auto Measurement mode is a recurring measurement reading of temperature and relative humidity, eliminating
the need to repeatedly initiate a measurement request through an I2C command. The measurement interval
can be adjusted from 1 measurement every 2 seconds to 1 measurement every second. In Auto Measurement
mode, the HDC302x wakes up from sleep to measurement mode based on the selected sampling rate.
Auto Measurement mode helps to reduce overall system power consumption in two ways. First, by removing
the need to repeatedly initiate a measurement through an I2C command, sink current through the SCL and SDA
pullup resistors is eliminated. Secondly, a microcontroller can be programmed into a deep sleep mode, and only
woken up through an interrupt by the ALERT pin in the event of excessive temperature and relative humidity
measurements.
7.3.7 Heater
The HDC302x includes an integrated heating element that can be switched on to prevent or remove
any condensation that may develop when the ambient environment approaches its dew point temperature.
Additionally, the heater can be used to verify functionally of the integrated temperature sensor.
If the dew point of an application is continuously calculated and tracked, and the application firmware is written
such that it can detect a potential condensing situation (or a period of it), a software subroutine can be run, as
a precautionary measure, to activate the onboard heater as an attempt to remove the condensate. The device
shall continue to measure and track the %RH level after the heater is activated. Once the %RH reading goes
to zero % (or near it), the heater can be subsequently turned off to allow the device to cool down. Cooling of
the device can take several minutes, but the temperature measurement will continue to run to ensure the device
goes back to normal operating condition before restarting the device for normal service.
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Note that when the heater activates, the operating temperature of the device shall be limited based on the
Recommended Operating Conditions THEATER limits.
It is important to recognize that the integrated heater evaporates condensate that forms on top of the humidity
sensor, but does not remove any dissolved contaminants. Any contaminant residue, if present, may impact the
accuracy of the humidity sensor.
7.3.8 ALERT Output With Programmable Interrupts
The ALERT output pin can be used to indicate when the HDC302x records a measurement that indicates either
the temperature and/or relative humidity result is outside of a programmed "comfort zone".
The ALERT output pin serves to drive circuit blocks where software monitoring is not feasible. Examples include
enabling a power switch to start a dehumidifier, or to initiate a thermal shutdown. Additionally, the ALERT pin
can minimize power drain by enabling a microcontroller to remain in deep sleep until environmental conditions
require the microcontroller to wake up and perform debug and corrective actions.
7.3.9 Checksum Calculation
Error checking of data is supported with a Checksum Calculation. The 8-bit CRC checksum transmitted after
each data word is generated by a CRC algorithm. Table 7-1 shows the CRC properties. The CRC covers the
contents of the two previously transmitted data bytes. To calculate the checksum, only these two previously
transmitted data bytes are used.
A CRC byte is sent by the HDC302x to the I2C controller in the following cases:
1. Following the transmission of a relative humidity measurement
2. Following the transmission of a temperature measurement
3. Following the transmission of the contents of the Table 7-12
4. Following the transmission of any of the programmed ALERT limit values (High Alert, Set; High Alert, Clear;
Low Alert, Set; Low Alert, Clear)
A CRC byte must be sent by the I2C controller to the HDC302x in the following cases:
1. Following the configuration of any of the ALERT limit values (High Alert, Set; High Alert, Clear; Low Alert,
Set; Low Alert, Clear).
Table 7-1. HDC302x CRC Properties
PROPERTY
Name
VALUE
CRC-8
Width
8 bit
Read and/or Write Data
0x31 (x8 + x5 + x4 + 1)
0xFF
Protected Data
Polynomial
Initialization
Reflect Input
Reflect Output
Final XOR
Examples
False
False
0x00
CRC of 0xABCD = 0x6F
Retrieving the CRC byte from the HDC302x is optional. A NACK can be issued by the I2C controller prior to
reception of the CRC byte to cancel, as shown in Figure 7-1 and Figure 7-2.
I2C Controller
HDC
HDC
S
HDC
Address
W
A
0x24
A
0x0B
A
Sr
R
A
MSB [T]
A
LSB [T]
A
CRC [T]
A
MSB [RH]
A
LSB [RH]
N
P
Address
Figure 7-1. Example I2C NACK to Discard CRC Byte Corresponding to Humidity Measurement Readout
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I2C Controller
HDC
HDC
S
HDC
Address
W
A
0x24
A
0x0B
A
Sr
R
A
MSB [T]
A
LSB [T]
N
P
Address
Figure 7-2. Example I2C NACK to Discard CRC Byte Corresponding to Temperature Measurement
Readout
7.3.10 Programmable Offset of Relative Humidity and Temperature Results
HDC302x allows for the user to program offset value after the device acquires its relative humidity and
temperature results. The offset value can only be used to add or subtract from the sensor measurement results.
7.4 Device Functional Modes
The HDC302x has two modes of operation: Sleep Mode and Measurement Mode.
7.4.1 Sleep Mode vs. Measurement Mode
Sleep mode is the default mode of the HDC302x upon Power Up/Cycle, Hard Reset through the RESET pin,
and Soft Reset. The HDC302x will wait for an I2C instruction to trigger a measurement, or to read and write valid
data. A measurement request will trigger the HDC302x to switch to measurement mode, where measurements
from the integrated sensors are passed through an internal ADC, and go through linearization using calibration
data from within the device to produce accurate calculations of temperature and relative humidity. The results
are stored in their respective data registers. After completing the conversion, the HDC302x returns to sleep
mode.
7.5 Programming
7.5.1 I2C Interface
The HDC302x operates only as a target device on the I2C bus. Multiple devices on the same I2C bus with the
same address are not allowed. Connection to the bus is made through the open-drain I/O lines, SCL and SDA.
After power-up, the sensor needs at most 3 ms to be ready to begin acquisition of temperature and relative
humidity measurements. All data bytes are transmitted MSB first.
7.5.2 I2C Serial Bus Address Configuration
An I2C controller will communicate to a desired target device through a target address byte. The target address
byte consists of seven address bits and a direction bit that indicates the intent to execute a read or write
operation. The HDC302x features two address pins, which allow for supporting four addressable HDC302x
devices on a single I2C bus. Table 7-2 describes the pin logic levels used to communicate up to four devices.
HDC302x pins ADDR and ADDR1 must be set before any activity on the interface occurs and remain constant
while the device is powered on.
Table 7-2. HDC302x I2C Target Address
ADDR
ADDR1
Logic Low or Open
Logic High
ADDRESS (Hex Representation)
Logic Low or Open
Logic Low or Open
Logic High
0x44
0x46
0x45
0x47
Logic Low or Open
Logic High
Logic High
7.5.3 I2C Write - Send Device Command
Communication to the HDC302x is based upon a command list, which is documented in Table 7-3. Commands
other than those documented are undefined and should not be sent to the device. An unsupported command
returns a NACK after the pointer, and a read or write operation with incorrect I2C address returns a NACK after
the I2C address.
An I2C write sequence is performed to send a command to the HDC302x. Some of these commands also
require configuration data from the I2C controller. In those instances, a CRC byte must accompany the
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configuration data to permit error checking by the HDC302x. Both of these I2C write scenarios are illustrated
in Figure 7-3 and Figure 7-4.
START
WRITE
STOP
I2C Controller
HDC
Command
(MSB)
Command
(LSB)
S
I2C Address
W
A
A
A
P
ACK
Figure 7-3. I2C Write Command, No Configuration Data Required
START
WRITE
W
STOP
P
I2C Controller
HDC
Command
(MSB)
Command
(LSB)
Data
(MSB)
Data
(LSB)
S
I2C Address
A
A
A
A
A
CRC
A
ACK
Figure 7-4. I2C Write Command, Configuration Data and CRC Byte Required
7.5.4 I2C Read - Retrieve Single Data Result
An I2C read sequence is performed to retrieve data from the HDC302x. The I2C read sequence must follow the
I2C write sequence that was used to initiate the data acquisition. A CRC byte always accompanies data that is
transmitted by the HDC302x. If the I2C controller does not use the CRC byte to perform a data integrity check,
then an I2C NACK can be issued to discard CRC transmission and save time. Both of these I2C read scenarios
are illustrated in Figure 7-5 and Figure 7-6.
START
READ
STOP
I2C Controller
HDC
Data
(MSB)
Data
(LSB)
S
I2C Address
R
A
A
N
P
ACK
NACK
Figure 7-5. I2C Read Single Data Result, CRC Discarded
START
READ
R
STOP
P
I2C Controller
HDC
Data
(MSB)
Data
(LSB)
S
I2C Address
A
A
A
CRC
N
ACK
NACK
Figure 7-6. I2C Read Single Data Result, CRC Retained
The HDC302x will stop transmission of a data byte if the I2C controller fails to ACK after any byte of data.
7.5.5 I2C Read - Retrieve Multi Data Result
When an I2C read sequence is performed to retrieve multiple data results and the I2C controller does not use the
CRC byte to perform a data integrity check, then an I2C NACK can be issued to only discard CRC transmission
from the final transmitted data result. Both of these I2C read scenarios are illustrated in Figure 7-7 and Figure
7-8.
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START
READ
R
STOP
P
I2C Controller
HDC
Data 1
(MSB)
Data 1
(LSB)
Data 2
(MSB)
Data 2
(LSB)
S
I2C Address
A
A
A
CRC
A
A
N
ACK
NACK
Figure 7-7. I2C Read Multi Data Result, Final CRC Discarded
START
READ
R
STOP
P
I2C Controller
HDC
Data 1
(MSB)
Data 1
(LSB)
Data 2
(MSB)
Data 2
(LSB)
S
I2C Address
A
A
A
CRC
A
A
A
CRC
N
ACK
NACK
Figure 7-8. I2C Read Multi Data Result, Final CRC Retained
7.5.6 I2C Repeated START - Send Command and Retrieve Data Results
HDC302x supports I2C repeated START, which enables the issue of a command and retrieval of data without
releasing the I2C bus. As with all other data retrieval requests, reception of the CRC byte corresponding to the
last data result may be discarded or retained. Both of these examples are illustrated in Figure 7-9 and Figure
7-10 for a single data result retrieval, and in Figure 7-11 and Figure 7-12 for a multi data result retrieval.
START
WRITE
REPEATED START
READ
STOP
I2C Controller
HDC
Command
(MSB)
Command
(LSB)
Data 1
(MSB)
Data 1
(LSB)
S
I2C Address
W
A
A
A
Sr I2C Address
R
A
A
N
P
ACK
NACK
Figure 7-9. I2C Repeated START Sequence, Single Data Result, CRC Discarded
START
WRITE
W
REPEATED START
READ
R
STOP
P
I2C Controller
HDC
Command
(MSB)
Command
(LSB)
Data 1
(MSB)
Data 1
(LSB)
S
I2C Address
A
A
A
Sr I2C Address
A
A
A
CRC
N
ACK
NACK
Figure 7-10. I2C Repeated START Sequence, Single Data Result, CRC Retained
START
WRITE
W
REPEATED START
READ
R
STOP
P
I2C Controller
Command
(MSB)
Command
(LSB)
Data 1
(MSB)
Data 1
(LSB)
Data 2
(MSB)
Data 2
(LSB)
S
I2C Address
A
A
A
Sr I2C Address
A
A
A
CRC
A
A
N
HDC
ACK
NACK
Figure 7-11. I2C Repeated START Sequence, Multi Data Result, Final CRC Discarded
START
WRITE
W
REPEATED START
READ
R
STOP
I2C Controller
HDC
Command
(MSB)
Command
(LSB)
Data 1
(MSB)
Data 1
(LSB)
Data 2
(MSB)
Data 2
(LSB)
S
I2C Address
A
A
A
Sr I2C Address
A
A
A
CRC
A
A
A
CRC
N
P
ACK
NACK
Figure 7-12. I2C Repeated START Sequence, Multi Data Result, Final CRC Retained
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7.5.7 Command Table and Detailed Description
The HDC302x command structure is documented below in Table 7-3. Details about each individual command
are documented in the subsections below.
Table 7-3. HDC302x Command Table
HEX CODE HEX CODE
COMMAND
COMMAND DETAIL
(MSB)
(LSB)
24
24
24
24
20
20
20
20
21
21
21
21
22
22
22
22
23
23
23
23
27
27
27
27
30
E0
E0
E0
E0
E0
61
61
61
61
00
0B
16
FF
32
24
2F
FF
30
26
2D
FF
36
20
2B
FF
34
22
29
FF
37
21
2A
FF
93
00
02
03
04
05
00
1D
0B
16
Low Power Mode 0 (lowest noise)
Low Power Mode 1
Trigger-On Demand Mode
Single Temperature (T) Measurement
Single Relative Humidity (RH) Measurement
Low Power Mode 2
Low Power Mode 3 (lowest power)
Low Power Mode 0 (lowest noise)
Low Power Mode 1
Auto Measurement Mode
1 measurement per 2 seconds.
Low Power Mode 2
Low Power Mode 3 (lowest power)
Low Power Mode 0 (lowest noise)
Low Power Mode 1
Auto Measurement Mode
1 measurement per second.
Low Power Mode 2
Low Power Mode 3 (lowest power)
Low Power Mode 0 (lowest noise)
Low Power Mode 1
Auto Measurement Mode
2 measurements per second.
Low Power Mode 2
Low Power Mode 3 (lowest power)
Low Power Mode 0 (lowest noise)
Low Power Mode 1
Auto Measurement Mode
4 measurements per second.
Low Power Mode 2
Low Power Mode 3 (lowest power)
Low Power Mode 0 (lowest noise)
Low Power Mode 1
Auto Measurement Mode
10 measurements per second.
Low Power Mode 2
Low Power Mode 3 (lowest power)
Exit, then return to Trigger-on Demand Mode.
Measurement Readout of T and RH.
Measurement History Readout of Minimum T.
Measurement History Readout of Maximum T.
Measurement History Readout of Minimum RH.
Measurement History Readout of Maximum RH.
Programs Thresholds for "Set Low Alert"
Programs Thresholds for "Set High Alert"
Programs Thresholds for "Clear Low Alert"
Programs Thresholds for "Clear High Alert"
Auto Measurement Mode
Configure ALERT Thresholds of T and RH
Verify ALERT Thresholds of T and RH
Transfer ALERT thresholds into Non-Volatile
Memory (NVM)
61
55
E1
E1
E1
E1
02
1F
09
14
Read Thresholds for "Set Low Alert"
Read Thresholds for "Set High Alert"
Read Thresholds for "Clear Low Alert"
Read Thresholds for "Clear High Alert"
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Table 7-3. HDC302x Command Table (continued)
HEX CODE HEX CODE
COMMAND
COMMAND DETAIL
(MSB)
(LSB)
30
30
F3
30
6D
66
2D
41
Enable
Integrated Heater
Disable
Read Content
Clear Content
Status Register
Program/Read offset value into/from non-volatile
memory
A0
04
30
36
36
36
37
A2
83
84
85
81
Soft Reset
Read NIST ID (Serial Number) Bytes 5 and 4
Read NIST ID (Serial Number) Bytes 3 and 2
Read NIST ID (Serial Number) Bytes 1 and 0
Read Manufacturer ID (Texas Instruments) (0x3000)
Override Default Device Power-On/Reset
Measurement State. Table 7-5 lists all valid
configuration values that may be sent as part of this
command.
61
BB
7.5.7.1 Reset
7.5.7.1.1 Soft Reset
The HDC302x provides a software command, as illustrated in Figure 7-13, to force itself into its default state
while maintaining supply voltage. It is the software equivalent to a hardware reset through the Power Cycle or
toggle of the RESET pin. When executed, the HDC302x will reset its Status Register, reload the calibration data
and programmed humidity/temperature offset error from memory, clear previously stored measurement results,
set Interrupt Thresholds limits back to their defaults, and re-configure the ALERT output to its default condition.
I2C Controller
S
I2C Address
W
A
0x30
A
0xA2
A
P
HDC
Figure 7-13. I2C Command Sequence: HDC302x Software Reset
7.5.7.1.2 I2C General Call Reset
In addition to the device-specific Soft Reset command, the HDC302x supports the general call address of the
I2C specification. This enables the use of a single command to reset an entire I2C system (provided that all
devices on the I2C bus support it). Figure 7-14 shows this command. The general call is recognized when the
sensor is able to process I2C commands and is functionally equivalent to the Software Reset.
I2C Controller
S
I2C Address
W
A
0x00
A
0x06
A
HDC
Figure 7-14. I2C Command Sequence: HDC302x Reset Through General Call
7.5.7.2 Trigger-On Demand
This set of commands will trigger a single measurement acquisition of temperature, followed by relative humidity.
The HDC302x will transition from sleep mode into measurement mode, and upon measurement completion,
return to sleep mode. There are four possible Trigger On Demand commands, each one corresponding to
a different low power mode (and therefore, different levels of power consumption). Table 7-3 shows these
commands.
The measurement readout from these commands is obtained through an I2C read sequence, as previously
documented in I2C Read - Retrieve Single Data Result and I2C Read - Retrieve Multi Data Result. The format of
the measurement readout is two bytes of data representing temperature, followed by one byte CRC checksum,
and then another two bytes of data representing relative humidity, followed by one byte CRC checksum as
illustrated in Figure 7-15.
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Trigger On Demand - Default Low Power Mode
Temperature
Relative Humidity
I2C Controller
HDC
T
(MSB)
T
(LSB)
RH
(MSB)
RH
(LSB)
S
I2C Address
W
A
0x24
A
0x00
A
Sr I2C Address
R
A
A
A
CRC
A
A
A
CRC
N
P
Figure 7-15. I2C Command Sequence: Example Measurement Readout in Trigger-On Demand Mode
If the I2C controller attempts to read the measurements results prior to measurement completion, the HDC302x
will respond with a NACK condition, as illustrated in Figure 7-16.
Measurement Not Ready
Temperature
Relative Humidity
Trigger On Demand - Default Low Power Mode
I2C Controller
HDC
T
(MSB)
T
(LSB)
RH
(MSB)
RH
(LSB)
S
I2C Address
W
A
0x24
A
0x00
A
Sr I2C Address
R
N
P
S
I2C Address
R
A
A
A
CRC
A
A
A
CRC
N
P
Figure 7-16. I2C Command Sequence: Example Measurement Not Ready in Trigger-On Demand Mode
7.5.7.3 Auto Measurement Mode
Auto Measurement mode forces the HDC302x to perform a temperature and relative humidity measurement at a
specific timing interval, removing the need for the I2C controller to repeatedly initiate a measurement acquisition.
This section gives additional details for each command
7.5.7.3.1 Auto Measurement Mode: Enable and Configure Measurement Interval
There are 20 possible timing intervals when Auto Measurement mode is enabled, (and therefore, different levels
of average power consumption). These commands are documented in Table 7-3. To avoid self-heating of the
temperature sensor, TI recommends to limit the sampling interval to no faster than 1 measurement/second, as
illustrated in Figure 7-17.
Auto Mode œ 1 measurement/second œ Default Low Power Mode
I2C Controller
S
I2C Address
W
A
0x21
A
0x30
A
P
HDC
Figure 7-17. I2C Command Sequence: Enable Auto Measurement mode at 1 Measurement per Second
7.5.7.3.2 Auto Measurement Mode: Measurement Readout
The latest measurement acquisition in Auto Measurement Mode can be retrieved using a measurement readout
command, which is documented in Table 7-3, and illustrated in Figure 7-18. Once the measurement readout is
complete, the HDC302x clears the measurement result from memory.
As in Trigger-On Demand, if the I2C controller attempts to read the measurement results prior to measurement
completion, the HDC302x will respond with a NACK condition.
Measurement Readout œ Auto Mode
Temperature
Relative Humidity
I2C Controller
HDC
T
(MSB)
T
(LSB)
RH
(MSB)
RH
(LSB)
S
I2C Address
W
A
0xE0
A
0x00
A
Sr I2C Address
R
A
A
A
CRC
A
A
A
CRC
N
P
Figure 7-18. I2C Command Sequence: Measurement Readout in Auto Measurement Mode
7.5.7.3.3 Auto Measurement Mode: Exit
The command to exit Auto Measurement mode is documented in Table 7-3 and illustrated in Figure 7-19. The
HDC302x will immediately discontinue any measurement in progress and return to sleep mode. This takes
typically 1 ms.
Exit Auto Mode
I2C Controller
HDC
S
I2C Address
W
A
0x30
A
0x93
A
P
Figure 7-19. I2C Command Sequence: Exit Auto Measurement Mode
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7.5.7.3.4 Auto Measurement Mode: Measurement History Readout
Within Auto Measurement Mode, the HDC302x maintains a history of the maximum and minimum measurement
for temperature and relative humidity (described as variables MIN T, MAX T, MIN RH, and MAX RH). This
feature is useful for scenarios where the user would like to assess if the ambient conditions ever approached,
but did not surpass, the defined environmental thresholds as documented in Section 7.5.7.4.1. Table 7-4
summarizes the status of MIN T, MAX T, MIN RH, and MAX RH based on device configuration.
Table 7-4. Status of Measurement History Variables based on HDC302x Configuration
HDC302x Configuration
Outside of Auto Measurement Mode
Within Auto Measurement Mode
MIN T
MAX T
MIN RH
MAX RH
130°C
-45°C
100%
0%
Monitored and Latched When Appropriate
Whenever the HDC302x exits Auto Measurement Mode (e.g. via Auto Measurement Mode: Exit, Soft Reset,
General Call Reset, or ), all four variables will return to their default values documented in Table 7-4. Therefore,
measurement history readouts outside of Auto Measurement Mode are invalid. Figure 7-20, Figure 7-21, Figure
7-22, and Figure 7-23 illustrate the I2C sequence for measurement readout of MIN T, MAX T, MIN RH, and MAX
RH.
Minimum Temperature Readout œ Auto Mode
I2C Controller
Min T
(MSB)
Min T
(LSB)
S
I2C Address
W
A
0xE0
A
0x01
A
Sr I2C Address
R
A
A
A
CRC
N
P
HDC
Figure 7-20. I2C Sequence: Minimum Temperature Measurement Readout (Auto Measurement Mode)
Maximum Temperature Readout œ Auto Mode
I2C Controller
Max T
(MSB)
Max T
(LSB)
S
I2C Address
W
A
0xE0
A
0x02
A
Sr I2C Address
R
A
A
A
CRC
N
P
HDC
Figure 7-21. I2C Sequence: Maximum Temperature Measurement Readout (Auto Measurement Mode)
Minimum Humidity Readout œ Auto Mode
I2C Controller
Min RH
(MSB)
Min RH
(LSB)
S
I2C Address
W
A
0xE0
A
0x03
A
Sr I2C Address
R
A
A
A
CRC
N
P
HDC
Figure 7-22. I2C Sequence: Minimum Relative Humidity Measurement Readout (Auto Measurement Mode)
Maximum Humidity Readout œ Auto Mode
I2C Controller
Max RH
(MSB)
Max RH
(LSB)
S
I2C Address
W
A
0xE0
A
0x04
A
Sr I2C Address
R
A
A
A
CRC
N
P
HDC
Figure 7-23. I2C Sequence: Maximum Relative Humidity Measurement Readout (Auto Measurement
Mode)
7.5.7.3.5 Override Default Device Power-On and Device-Reset State
The HDC302x defaults to entering sleep mode after a device power-on or a device-reset. However, an override
command may be sent to the HDC302x to force entry into Automatic Measurement mode upon every device
power-on and device-reset. The command is illustrated in below in Figure 7-24 and the list of all possible
command configurations is documented in Table 7-5.
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Measurement Default
Configuration
I2C Controller
HDC
CFG
(MSB)
CFG
(LSB)
S
I2C Address
W
A
0x61
A
0xBB
A
A
A
CRC
A
P
Figure 7-24. I2C Sequence: Configure Default Measurement
Table 7-5 lists all valid configuration values that may be sent as part of this command.
Table 7-5. List of Valid Measurement Configuration Values to send to HDC302x
CFG (MSB) CFG (LSB)
CRC
0xB0
0xD2
0x74
0x16
0x09
0xF3
0x91
0x37
0x55
0x4A
0x36
0x54
0xF2
0x90
0x8F
0x75
0x17
0xB1
0xD3
0xCC
Configuration
Low Power Mode
Measurements per Second
0x03
0x05
0x07
0x09
0x0B
0x13
0x15
0x17
0x19
0x1B
Automatic Measurement Mode
Automatic Measurement Mode
Automatic Measurement Mode
Automatic Measurement Mode
Automatic Measurement Mode
Automatic Measurement Mode
Automatic Measurement Mode
Automatic Measurement Mode
Automatic Measurement Mode
Automatic Measurement Mode
Automatic Measurement Mode
Automatic Measurement Mode
Automatic Measurement Mode
Automatic Measurement Mode
Automatic Measurement Mode
Automatic Measurement Mode
Automatic Measurement Mode
Automatic Measurement Mode
Automatic Measurement Mode
Automatic Measurement Mode
0 (lowest noise)
0.5
1
0 (lowest noise)
0 (lowest noise)
2
0 (lowest noise)
4
0 (lowest noise)
10
0.5
1
1
1
1
2
1
4
1
10
0.5
1
0x23
0x00
2
0x25
0x27
0x29
0x2B
0x33
0x35
0x37
0x39
0x3B
2
2
2
2
4
2
10
0.5
1
3 (lowest power)
3 (lowest power)
3 (lowest power)
3 (lowest power)
3 (lowest power)
2
4
10
Restores Factory Default (Sleep
Mode)
0x00
0x81
N/A
N/A
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7.5.7.4 ALERT Output Configuration
The HDC302x provides hardware notification of events through an interrupt output pin (ALERT). Specifically,
the ALERT output represents the status of bits 15, 11, 10, and 4 from the Status Register Section 7.5.7.6. The
ALERT output asserts to Logic High upon detection of an event and de-asserts to Logic Low when the event has
passed or after the Status Register Section 7.5.7.6 is cleared.
The ALERT output is activated by default upon Power Up, Hardware Reset, and Soft Reset. It is deactivated
when the HDC302x has been disabled via assertion of the RESET pin. When deactivated, the HDC302x will
clear the Status Register Section 7.5.7.6.
If temperature and relative humidity tracking through the ALERT output is not desired, the feature can be
disabled as explained in Section 7.5.7.4.4
7.5.7.4.1 ALERT Output: Environmental Tracking of Temperature and Relative Humidity
The primary use of the ALERT output is to provide a hardware notification of ambient temperature and relative
humidity measurements that violate programmed thresholds. There are a total of four programmable thresholds
for temperature and relative humidity, as documented in Table 7-3 and illustrated in Figure 7-25 below.
Measured RH/T
Set High Alert
Clear High Alert
Clear Low Alert
Set Low Alert
Time
ALERT
VOH
VOL
Time
Figure 7-25. Graphical Illustration of ALERT Programmable Environmental Thresholds
The four programmable thresholds are listed below
1. Set High Alert: Asserts ALERT output when HDC302x measures a temperature or relative humidity level
that has risen above this value.
2. Clear High Alert: Deasserts the ALERT output caused by Set High Alert, once HDC302x measures a
temperature or relative humidity level that has fallen below this value.
3. Set Low Alert: Programmed value that asserts ALERT output when HDC302x measures a temperature or
relative humidity level that has fallen below this value.
4. Clear Low Alert: Programmed value that deasserts the ALERT output caused by Set Low Alert, once
HDC302x measures a temperature of relative humidity level that has risen above this value.
If the user application utilizes the ALERT output for environmental tracking, it is best practice to program these
four thresholds prior to any temperature or relative humidity measurement acquisition. Programming enough
separation between the Set versus Clear thresholds will prevent fast oscillations of the ALERT output.
These programmed limits are accessible at any time of operation .
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7.5.7.4.2 ALERT Output: Representation of Environmental Thresholds and Default Threshold Values
The Set High Alert, Clear High Alert, Set Low Alert, and Clear Low Alert thresholds are each represented
by a truncated 16 bit value, as illustrated Figure 7-26. The 7 MSBs from a relative humidity measurement
are concatenated with the 9 MSBs from a temperature measurement. The actual temperature and relative
humidity measurement result are always stored as a 16-bit value, but when compared against the programmed
threshold values, due to the truncated representation, there is a resolution loss of 0.5°C in temperature and a
1% resolution loss in relative humidity.
16-Bit RH Measurement (MSB to LSB)
15 14 13 12 11 10
16-Bit T Measurement (MSB to LSB)
15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
9
8
7
6
5
4
3
2
1
0
15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
Combined 16-Bit RH and T Threshold (MSB to LSB)
Figure 7-26. Representation of ALERT Threshold Value Using Combined RH and T
The default values of the relative humidity and temperature thresholds after Power Up/Cycle, Hardware Reset,
and Soft Reset are documented in Table 7-6 below. Refer to Table 7-3 for the appropriate command to re-
program the thresholds.
Table 7-6. Default Value of ALERT Thresholds
ALERT THRESHOLD
Set High Alert
DEFAULT RH THRESHOLD
DEFAULT T THRESHOLD
HEX VALUE
0xCD33
0xC92D
0x3466
CRC
0xFD
0x22
0xAD
0x37
80% RH
79% RH
20% RH
22% RH
60°C
58°C
-10°C
-9°C
Clear High Alert
Set Low Alert
Clear Low Alert
0x3869
7.5.7.4.3 ALERT Output: Steps to Calculate and Program Environmental Thresholds
The steps to calculate the Set High Alert, Clear High Alert, Set Low Alert, and Clear Low Alert thresholds are
listed below:
1. Select the desired relative humidity and temperature threshold to program, and the programmed value.
2. Convert the relative humidity and temperature threshold value to its respective 16-bit binary value
3. Retain the 7 MSBs for relative humidity and the 9 MSBs for temperature
4. Concatenate the 7 MSBs for relative humidity with the 9 MSBs for temperature to complete the 16-bit
threshold representation
5. Calculate the CRC byte from the 16-bit threshold value
An example is provided below.
1. In this case, the Set High Alert threshold will be programmed to 90% RH and 65°C
2. 90% RH converts to 0b1110011001100111 and 65°C T converts to 0b1010000011101011
3. 7 MSBs for 90% RH is 0b1110011 and 9 MSBs for 65°C T is 0b101000001
4. After concatenation of the relative humidity and temperature MSBs, the threshold representation is
0b1110011101000001 = 0xE741
5. For 0xE741, this corresponds to a CRC byte 0x55
a. Figure 7-27 illustrates the appropriate command to send to the HDC302x.
b. The HDC302x will respond to reception of an incorrect CRC byte with a I2C NACK.
Set High Alert
90%RH, 65°C
CRC
I2C Controller
HDC
S
I2C Address
W
A
0x61
A
0x1D
A
0xE7
A
0x41
A
0x55
A
P
Figure 7-27. I2C Command Sequence: Example Programming of Set High Alert to 90% RH, 65°C
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7.5.7.4.4 ALERT Output: Deactivation of Environmental Tracking
To deactivate the ALERT output from responding to measurement results of temperature and/or relative
humidity, the Set High Alert thresholds must be programmed to be lower than the Set Low Alert thresholds.
Figure 7-28 illustrates an example of threshold programming that disables tracking of temperature as well as
relative humidity. To be more specific:
•
To disable Temperature Alert Tracking: Configure the temperature bits within the Set Low Alert threshold to
be larger than the temperature bits within the Set High Alert threshold.
•
To disable Humidity Alert Tracking: Configure the humidity bits within the Set Low Alert threshold to be larger
than the humidity bits within the Set High Alert threshold.
Set Low Alert
100%RH, 130°C
CRC
Set High Alert
0%RH, -45°C
CRC
I2C Controller
HDC
S
I2C Address
W
A
0x61
A
0x00
A
0xFF
A
0xFF
A
0xAC
A
Sr I2C Address
W
A
0x61
A
0x1D
A
0x00
A
0x00
A
0x81
A
P
Figure 7-28. I2C Command Sequence: Example to Deactivate ALERT Output Tracking of Temperature and
Relative Humidity
7.5.7.4.5 ALERT Output: Transfer Thresholds into Non-Volatile Memory
This command, illustrated below in Figure 7-29, enables an override of the default ALERT threshold values
after a device reset or power cycle. This permits independent assembly of a sensor board and a remote MCU
board. Normally, the MCU is local to the sensor (that is, they share a common board) and the MCU will program
the threshold values. However, there are applications where the sensor and MCU are on separate boards,
and deployed to various applications, each with unique threshold requirements. This normally adds significant
tracking overhead (that is, each MCU board must be assigned to a specific sensor board). With this feature, the
HDC302x thresholds may be configured using a debugger/programmer during product assembly, and later on,
connected to any MCU board on its own assembly, with the application-specific thresholds already ensured.
NVM Transfer of ALERT Thresholds
I2C Controller
HDC
S
I2C Address
W
A
0x61
A
0x55
A
P
Figure 7-29. I2C Command Sequence: Transfer ALERT Thresholds into NVM
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7.5.7.5 Programmable Measurement Offset
The HDC302x can be programmed to return a relative humidity measurement and/or a temperature
measurement that accounts for a programmed offset value. An operation bit determines whether to add or
subtract the offset from the actual sensor measurement results. This feature is targeted for designs where
local heat sources can not be isolated from the temperature sensor and said heat sources show variation over
time (due to different components being enabled/disabled). The command is documented in the Table 7-3. The
device should be in shutdown mode when changing the offset because if it is in Auto Measurement mode. it
could give unpredictable results.
Programming either offset value requires programming of a corresponding non-volatile memory location in the
EEPROM. Therefore, I2C writes are not permitted until offset programming is complete. Refer to the electrical
characteristics table tOS_PROG parameters for the time to complete a programming a single location. The
HDC302x will draw approximately 230 µA during offset programming.
7.5.7.5.1 Representation of Offset Value and Factory Shipped Default Value
As illustrated in Figure 7-30, the programmed offset values for relative humidity (RHOS) and temperature (TOS
)
are combined into a single 16-bit representation. 7 bits represent RHOS, 7 bits represent TOS, 1 operation
bit (RH+/-) to add or subtract RHOS, and 1 operation bit (T+/-) to add or subtract TOS. From the 16-bit
representation of relative humidity, bits 13 through 7 are used to represent RHOS. From the 16-bit representation
of temperature, bits 12 through 6 are used to represent TOS
.
16-Bit Representation of Relative Humidity (MSB to LSB)
16-Bit Representation of Temperature (MSB to LSB)
15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
RH15 RH14 RH13 RH12 RH11 RH10 RH9 RH8 RH7 RH6 RH5 RH4 RH3 RH2 RH1 RH0
T15 T14 T13 T12 T11 T10 T9
T8
T7
T6
T5
T4
T3
T2
T1
T0
15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
RH+/- RH13 RH12 RH11 RH10 RH9 RH8 RH7 T+/- T12 T11 T10 T9
T8
T7
T6
RHOS
TOS
16-Bit Combined RH and T Offset (MSB to LSB)
Figure 7-30. Data Structure to Represent Programmed Offset Values for RH and T
7.5.7.5.2 Factory Shipped Default Offset Values
The HDC302x is factory-shipped with default values of RHOS and TOS as documented in Table 7-7.
Table 7-7. Factory Shipped Default Offset Value
DEFAULT RHOS [%]
DEFAULT TOS [°C]
HEX VALUE (0x)
CRC (0x)
0
0
00 00
81
7.5.7.5.3 Calculate Relative Humidity Offset Value
Table 7-8 documents the programmed offset value that is represented by each individual relative humidity offset
bit within RHOS. The minimum programmable offset is 0.1953125% and the maximum programmable offset is
24.8046875%.
Table 7-8. Relative Humidity Offset Value (RHOS) Represented by Each Data Bit
RH OFFSET BIT
VALUE WHEN PROGRAMMED TO 0
VALUE WHEN PROGRAMMED TO 1
RH+/-
Subtract
Add
12.5
RH13
0
0
0
0
0
0
RH12
6.25
RH11
3.125
RH10
1.5625
0.78125
0.390625
RH9
RH8
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Table 7-8. Relative Humidity Offset Value (RHOS) Represented by Each Data Bit (continued)
RH OFFSET BIT
VALUE WHEN PROGRAMMED TO 0
VALUE WHEN PROGRAMMED TO 1
RH7
0
0.1953125
Table 7-9 below gives an example of some of the possible calculated relative humidity offset values (including
the operation bit RH+/-):
Table 7-9. Example Programmed Values of RHOS
RH+/-
RH13
RH12
RH11
RH10
RH9
RH8
RH7
RH OFFSET VALUE
+0.1952125% RH
-0.1952125% RH
+12.5% RH
1
0
1
0
1
0
1
0
0
0
1
1
0
0
1
1
0
0
0
0
1
1
1
1
0
0
0
0
0
0
1
1
0
0
0
0
1
1
1
1
0
0
1
0
0
1
0
0
0
0
0
0
-12.5% RH
0
1
0
+8.203125% RH
-8.203125% RH
+24.8046875% RH
-24.8046875% RH
0
1
0
1
1
1
1
1
1
7.5.7.5.4 Calculate Temperature Offset Value
Table 7-10 documents the programmed offset value that is represented by each individual relative temperature
offset bit within TOS. The minimum programmable offset is 0.1708984375°C and the maximum programmable
offset is 21.7041015625°C.
Table 7-10. Temperature Offset Value (TOS) Represented by Each Data Bit
T OFFSET BIT
VALUE WHEN PROGRAMMED TO 0
VALUE WHEN PROGRAMMED TO 1
T+/-
T12
T11
T10
T9
Subtract
Add
0
0
0
0
0
0
0
10.9375
5.46875
2.734375
1.3671875
0.68359375
0.341796875
0.1708984375
T8
T7
T6
Table 7-11 below gives an example of some of the possible calculated temperature offset values (including the
operation bit T+/-):
Table 7-11. Example Programmed Values of TOS
T+/-
1
T12
0
T11
0
T10
T9
0
0
0
0
1
1
1
1
T8
0
0
0
0
0
0
1
1
T7
0
0
0
0
1
1
1
1
T6
1
1
0
0
0
0
1
1
T OFFSET VALUE
+0.1708984375°C
-0.1708984375°C
+10.9375°C
0
0
0
0
0
1
1
0
0
0
1
0
0
-10.9375°C
1
0
1
0
+7.177734375°C
-7.177734375°C
21.7041015625°C
-21.7041015625°C
0
0
1
0
1
1
1
1
0
1
1
1
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7.5.7.5.5 Write an Offset Value
After determining the desired value of RH+/-, RHOS, T+/-, and TOS, as documented in Calculate Relative Humidity
Offset Value and Calculate Temperature Offset Value, determine the correct CRC checksum and send all three
bytes to the HDC302x as illustrated in Figure 7-31 (along with an example scenario of +8.20% RH and –7.17°C).
Access RH+T Offset
I2C Controller
S
I2C Address
W
A
0xA0
A
0x04
A
RH+/-, RHOS
A
T+/-, TOS
A
CRC
A
P
HDC
Access RH+T Offset +8.20%RH, -7.17°C
CRC
I2C Controller
HDC
S
I2C Address
W
A
0xA0
A
0x04
A
0xAA
A
0x33
A
0xAC
A
P
Figure 7-31. I2C Command Sequence: RH and T Offset (Example With +8.20% RH and –7.17°C)
7.5.7.5.6 Verify a Programmed Offset Value
The command to verify the programmed offset values is documented in Table 7-3 and the command sequence is
illustrated in Figure 7-32.
Access RH+T offset
I2C Controller
HDC
S
I2C Address
W
A
0xA0
A
0x04
A
Sr I2C Address
R
A
RH+/-, RHOS
A
T+/-, TOS
A
CRC
N
P
Figure 7-32. I2C Command Sequence: Verify Programmed RH and T Offset
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7.5.7.6 Status Register
The Status Register contains real-time information about the operating state of the HDC302x, as documented in
Table 7-12. There are two commands associated with the Status Register: Read Content and Clear Content, as
documented in Table 7-3 and illustrated in Figure 7-33 and Figure 7-34.
Table 7-12. Customer View: Status Register
BIT
15
14
13
12
11
DEFAULT
DESCRIPTION
Overall Alert Status
0 = No active alerts
1 = At least one active alert
1
0
0
0
0
Reserved
Heater Status
0 = Heater Disabled
1 = Heater Enabled
Reserved
RH Tracking Alert
0 = No RH alert
1 = RH alert
T Tracking Alert
0 = No T alert
1 = T alert
10
9
0
0
0
0
RH High Tracking Alert
0 = No RH High alert
1 = RH High alert
RH Low Tracking Alert
0 = No RH Low alert
1 = RH Low alert
8
T High Tracking Alert
0 = No T High alert
1 = T High alert
7
T Low Tracking Alert
0 = No T Low alert
1 = T Low alert
6
5
4
0
0
1
Reserved
Device Reset Detected
0 = No reset detected since last clearing of Status Register
1 = Device reset detected (via hard reset, soft reset command or supply fail)
3
2
1
0
0
0
Reserved
Reserved
Reserved
Checksum verification of last data write
0 = Pass (correct checksum received)
1 = Fail (incorrect checksum received)
0
0
Status Register Readout
Bits 15-8
Bits 7-0
I2C Controller
HDC
Status
(MSB)
Status
(LSB)
S
I2C Address
W
A
0xF3
A
0x2D
A
Sr I2C Address
R
A
A
A
CRC
N
P
Figure 7-33. I2C Command Sequence: Read Status Register
Clear Status Register
I2C Controller
HDC
S
I2C Address
W
A
0x30
A
0x41
A
P
Figure 7-34. I2C Command Sequence: Clear Status Register
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7.5.7.7 Heater: Enable and Disable
The HDC302x includes an integrated heater with enough current draw (up to 45 mA) to enable operation in
condensing environments. The heater protects the humidity sensor area by preventing condensation as well as
removing condensate. Enabling and disabling of the heater is documented in Table 7-3 and illustrated in Figure
7-35 and Figure 7-36.
The heater is expected to impact the temperature measurement result and the relative humidity measurement
result. An IC-based humidity sensor uses the die temperature as an estimate for the ambient temperature. Use
of the heater will increase the die temperature up to 60°C above ambient temperature. Therefore, accurate
measurement results of ambient temperature and relative humidity are not possible when the heater is in
operation.
As long as condensate is present on the RH sensor, the measurement reading will continue to be > 99%.
Continue enabling the heater until the RH measurement reading falls to below 80%. In most cases, 2-3 minutes
of heater enable time is sufficient. It is best practice to ensure that the ambient temperature is higher than the
dew point temperature.
It is important to recognize that the integrated heater will evaporate condensate that forms on top of the humidity
sensor, but does not remove any dissolved contaminants. This contaminant residue, if present, may impact the
accuracy of the humidity sensor.
Enable Heater
I2C Controller
HDC
S
I2C Address
W
A
0x30
A
0x6D
A
P
Figure 7-35. I2C Command Sequence: Enable Heater
Disable Heater
I2C Controller
HDC
S
I2C Address
W
A
0x30
A
0x66
A
P
Figure 7-36. I2C Command Sequence: Disable Heater
7.5.7.8 Read NIST ID/Serial Number
Each HDC302x is configured with a unique 48-bit value that is used to support NIST traceability of the
temperature and relative humidity sensor. It can also be used to represent the unique serial number for that
device. Three commands are required to read the full 48-bit value as illustrated in Figure 7-37, Figure 7-38, and
Figure 7-39. Each command will return two bytes of NIST ID followed by a CRC byte. From MSB to LSB, the full
device NIST ID is read as NIST_ID_5, NIST_ID_4, NIST_ID_3, NIST_ID_2, NIST_ID_1, and NIST_ID_0.
Read NIST ID Bytes 5 and 4
I2C Controller
HDC
S
I2C Address
W
A
0x36
A
0x84
A
Sr I2C Address
R
A
NIST_ID_5
A
NIST_ID_4
A
CRC
N
P
Figure 7-37. I2C Command Sequence: Read NIST ID (Bytes NIST_ID_5, Then NIST_ID_4)
Read NIST ID Bytes 3 and 2
I2C Controller
HDC
S
I2C Address
W
A
0x36
A
0x84
A
Sr I2C Address
R
A
NIST_ID_3
A
NIST_ID_2
A
CRC
N
P
Figure 7-38. I2C Command Sequence: Read NIST ID (Bytes NIST_ID_3, Then NIST_ID_2)
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Read NIST ID Bytes 1 and 0
I2C Controller
HDC
S
I2C Address
W
A
0x36
A
0x85
A
Sr I2C Address
R
A
NIST_ID_1
A
NIST_ID_0
A
CRC
N
P
Figure 7-39. I2C Command Sequence: Read NIST ID (Bytes NIST_ID_1, Then NIST_ID_0)
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8 Application and Implementation
Note
Information in the following applications sections is not part of the TI component specification,
and TI does not warrant its accuracy or completeness. TI’s customers are responsible for
determining suitability of components for their purposes, as well as validating and testing their design
implementation to confirm system functionality.
8.1 Application Information
The HDC302x is used to measure the relative humidity and temperature of the board location where the device
is mounted. The programmable I2C address option allow up to four locations be monitored on a single serial bus.
8.2 Typical Application
One common application which requires a relative humidity and temperature sensor is a HVAC system
thermostat control. It is based on environmental sensors and a microcontroller. The microcontroller acquires data
from humidity and temperature sensors and controls the heating and cooling system. The collected data are then
shown on a display that can be easily controlled by the microcontroller. Based on data from the humidity and
temperature sensor, the heating and cooling system then maintains the environment at the customer-defined
preferred conditions.
In a battery-powered HVAC system thermostat, one of the key parameters in the selection of components is
the power consumption. The HDC302x, with 550 nA of current consumption (the average consumption over 1
s for RH and Temperature measurements), in conjunction with a MSP430, represents one way an engineer can
obtain low power consumption and extend battery life. A system block diagram of a battery-powered thermostat
is shown in Figure 8-1.
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DISPLAY
TEMPERATURE: 25°C/ 77°F
Relative Humidity (RH): 40%
Lithium
Ion Battery
+
-
TIME: XX:XX
DATE: XX:XX:XX
1.8V
VDD
1.8V
VDD
HDC3020
MCU
RH
Sensor
Violet
SCL
SDA
INT
ADDR
I2C Peripheral
GPIOs
Registers/
Logic
I2C
Interface
Red
e g a r n O
Red
MUX
Red
Red
ADC
GPIO
TVeiomletp
Sensor
GND
Calibration
Red
Coefficients
GND
KEYPAD
Button1
Button2
C
Button3
Button4
Figure 8-1. Typical Application Schematic HVAC
8.2.1 Design Requirements
To improve measurement accuracy, TI recommends to isolate the HDC302x from all heat sources in the form
of active circuitry, batteries, displays and resistive elements. If design space is a constraint, cutouts surrounding
the device or the inclusion of small trenches can help minimize heat transfer from PCB heat sources to the
HDC302x. To avoid self-heating the HDC302x, TI recommends to configure the device to no faster than 1
measurement/second.
The HDC302x operates only as a target device and communicates with the host through the I2C-compatible
serial interface. SCL is an input pin, SDA is a bidirectional pin, and ALERT is an output. The HDC302x requires
a pullup resistor on the SDA. An SCL pullup resistor is required if the system microprocessor SCL pin is
open-drain. The recommended value for the pullup resistors is 5 kΩ. In some applications, the pullup resistor
can be lower or higher than 5 kΩ. A 0.1-µF bypass capacitor is recommended to be connected between V+
and GND. Use a ceramic capacitor type with a temperature rating that matches the operating range of the
application, and place the capacitor as close as possible to the VDD pin of the HDC302x. The ADDR and
ADDR0 pins should be connected directly to GND, VDD, or left open for address selection of four possible
unique target ID addresses per the addressing scheme Table 7-2. The ALERT output pin can be connected to a
microcontroller interrupt that triggers an event that occurred when the relative humidity and/or temperature limit
exceeds the programmed value. The ALERT pin should be left floating when not in use.
8.2.2 Detailed Design Procedure
When a circuit board layout is created from the schematic shown in Figure 8-1, a small circuit board is possible.
The accuracy of a temperature and relative humidity measurement is dependent upon the sensor accuracy
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and the setup of the sensing system. Since the HDC302x measures relative humidity and temperature in its
immediate environment, it is critical that the local conditions at the sensor match the ambient environment. Use
one or more openings in the physical cover of the thermostat to obtain a good airflow even in static conditions.
Refer to the layout (Figure 10-1) for a PCB layout which minimizes the thermal mass of the PCB in the region of
the HDC302x, which can improve measurement response time and accuracy.
8.2.3 Application Curve
These results were acquired at TA = 25°C using a humidity chamber that sweeps RH%. The sweep profile used
was 10% > 20% > 30% > 40% > 50% > 60% > 70% > 80% > 70% > 60% > 50% > 40% > 30% > 20% > 10%.
Each RH% set point was held for 20 minutes.
TBD
Figure 8-2. RH% Readings of Chamber and HDC302x vs. Time
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9 Power Supply Recommendations
The HDC302x supports a voltage supply range from 1.62 V up to 5.50 V. TI recommends a multilayer ceramic
bypass X7R capacitor of 0.1 µF between the VDD and GND pins.
10 Layout
10.1 Layout Guidelines
Proper PCB layout of the HDC302x is critical to obtaining accurate measurements of temperature and relative
humidity. Therefore, TI recommends to:
1. Isolate all heat sources from the HDC302x. This means positioning the HDC302x away from power intensive
board components such as a battery, display, or micrcocontroller. As illustrated in Figure 10-1, ideally the
only onboard component close to the HDC302x is the supply bypass capacitor.
2. Eliminate copper layers below the device (GND, VDD
)
3. Use slots or a cutout around the device to reduce the thermal mass and obtain a quicker response time to
sudden environmental changes.
•
The diameter of the cutout around the part in this case is approximately 6 mm. The important details are
to implement a separation of thermal planes while allowing for power, ground and data lines and place
the part on the board, while still meeting mechanical assembly requirements. In addition Figure 10-1
other representations of cutouts for thermal relief can be found in SNAA297 section 2.3.
4. Follow the Example Board Layout and Example Stencil Design that is illustrated in Mechanical, Packaging,
and Orderable Information.
•
The SCL and the SDA lines require pull up resistors and TI recommends to connect a 0.1-uF cap to the
VDD line.
•
TI recommends a multilayer ceramic bypass X7R capacitor of 0.1 μF between the VDD and GND pins.
5. It is generally best practice to solder the package thermal pad to a board pad that is connected to ground,
however to minimize thermal mass for maximum heater efficiency or to measure ambient temperature it may
be left floating. Floating the thermal pad is an option because the thermal pad has a non-conductive epoxy.
See HDC3x Silicon User guide for more information regarding when leaving the thermal pad floating may be
helpful. for your application
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10.2 Layout Example
Figure 10-1. HDC302x PCB Layout Example
10.3 Storage and PCB Assembly
10.3.1 Storage and Handling
As with all humidity sensors, the HDC302x must follow special guidelines regarding handling and storage that
are not common with standard semiconductor devices. Long exposure to UV and visible light, or exposure to
chemical vapors for prolonged periods, should be avoided as it may affect RH% accuracy. Additionally, the
device should be protected from out-gassed solvent vapors produced during manufacturing, transport, operation,
and package materials (that is, adhesive tapes, stickers, bubble foils). For further detailed information, see
HDC3x Silicon User's Guide (SNAU265)
10.3.2 Soldering Reflow
For PCB assembly, standard reflow soldering ovens may be used. The HDC302x uses the standard soldering
profile IPC/JEDEC J-STD-020 with peak temperatures at 260°C. When soldering the HDC302x, it is mandatory
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to use no-clean solder paste, and the paste must not be exposed to water or solvent rinses during assembly
because these contaminants may affect sensor accuracy. After reflow, it is expected that the sensor will
generally output a shift in relative humidity, which will reduce over time as the sensor is exposed to typical indoor
ambient conditions. These conditions include 30-40% RH at room temperature during a duration of several
days. Following this rehydration procedure allows the polymer to correctly settle after reflow and return to the
calibrated RH accuracy.
10.3.3 Rework
TI recommends to limit the HDC302x to a single IR reflow with no rework, but a second reflow may be possible if
the following guidelines are met:
•
•
•
The exposed polymer (humidity sensor) is kept clean and undamaged.
No-clean solder paste is used and the process is not exposed to any liquids, such as water or solvents.
The peak soldering temperature does not exceed 260°C.
10.3.4 Exposure to High Temperature and High Humidity Conditions
Long exposure outside the recommended operating conditions may temporarily offset the RH output. The
recommended humidity operating range is 10 to 90% RH (non-condensing) over -20°C to 70°C. Prolonged
operation beyond these ranges may shift the sensor reading with a slow recovery time.
10.3.5 Bake/Rehydration Procedure
Prolonged exposure to extreme conditions or harsh contaminants may impact sensor performance. In the case
that permanent offset is observed from contaminants, the following procedure is suggested, which may recover
or reduce the error observed in sensor performance:
1. Baking: 100°C, at less than 5%RH, for 5 to 10 hours
2. Rehydration: Between 20°C to 30°C, 60%RH to 75%RH, for 6 to 12 hours
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11 Device and Documentation Support
11.1 Documentation Support
11.1.1 Related Documentation
For related documentation, see the following:
•
•
•
Texas Instruments, Humidity Sensor: Storage and Handling Guidelines application report (SNIA025)
Texas Instruments, Optimizing Placement and Routing for Humidity Sensors application report (SNAA297)
Texas Instruments, HDC3x Silicon User's Guide (SNAU265)
11.2 Receiving Notification of Documentation Updates
To receive notification of documentation updates, navigate to the device product folder on ti.com. Click on
Subscribe to updates to register and receive a weekly digest of any product information that has changed. For
change details, review the revision history included in any revised document.
11.3 Support Resources
TI E2E™ support forums are an engineer's go-to source for fast, verified answers and design help — straight
from the experts. Search existing answers or ask your own question to get the quick design help you need.
Linked content is provided "AS IS" by the respective contributors. They do not constitute TI specifications and do
not necessarily reflect TI's views; see TI's Terms of Use.
11.4 Trademarks
TI E2E™ is a trademark of Texas Instruments.
All trademarks are the property of their respective owners.
11.5 Electrostatic Discharge Caution
This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled
with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may
be more susceptible to damage because very small parametric changes could cause the device not to meet its published
specifications.
11.6 Glossary
TI Glossary
This glossary lists and explains terms, acronyms, and definitions.
12 Mechanical, Packaging, and Orderable Information
The following pages include mechanical, packaging, and orderable information. This information is the most
current data available for the designated devices. This data is subject to change without notice and revision of
this document. For browser-based versions of this data sheet, refer to the left-hand navigation.
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Figure 12-1. HDC3020 Package Outline Drawing
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Figure 12-2. HDC3020 Example Board Layout
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Figure 12-3. HDC3020 Example Stencil Design
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Figure 12-4. HDC3020 Package Outline Drawing
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Figure 12-5. HDC3021 Example Board Layout
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Figure 12-6. HDC3021 Example Stencil Design
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HDC3021
Figure 12-7. Package Outline Drawing
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Figure 12-8. HDC3022 Example Board Layout
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Figure 12-9. HDC3022 Example Stencil Design
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12.1 Package Option Addendum
Packaging Information
Orderable
Device
Package
Drawing
Lead/Ball
Finish(6)
MSL Peak
Temp(3)
Device
Status(1)
Package Type
Pins
Package Qty
Eco Plan(2)
Op Temp (°C)
Marking(4) (5)
PHDC3020DEF ACTIVE
T
WSON
DEF
DEH
DEJ
DEF
DEF
DEH
DEH
DEJ
DEJ
8
250
RoHS & Green NIPDAU
RoHS & Green NIPDAU
RoHS & Green NIPDAU
RoHS & Green NIPDAU
RoHS & Green NIPDAU
RoHS & Green NIPDAU
RoHS & Green NIPDAU
RoHS & Green NIPDAU
RoHS & Green NIPDAU
Level-1-260C- -40°C to 125°C
UNLIM
G
H
J
PHDC3021DE PREVIEW
HT
WSON
WSON
WSON
WSON
WSON
WSON
WSON
WSON
8
8
8
8
8
8
8
8
250
-40°C to 125°C
PHDC3022DEJ PREVIEW
T
250
Level-1-260C- -40°C to 125°C
UNLIM
HDC3020DEFR PRE_PROD
3000
250
Level-1-260C- -40°C to 125°C
UNLIM
G
G
H
H
J
HDC3020DEFT PRE_PROD
Level-1-260C- -40°C to 125°C
UNLIM
HDC3021DEH PRE_PROD
R
3000
250
Level-1-260C- -40°C to 125°C
UNLIM
HDC3021DEHT PRE_PROD
HDC3022DEJR PRE_PROD
HDC3022DEJT PRE_PROD
Level-1-260C- -40°C to 125°C
UNLIM
3000
250
Level-1-260C- -40°C to 125°C
UNLIM
Level-1-260C-
UNLIM
J
(1) The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PRE_PROD Unannounced device, not in production, not available for mass market, nor on the web, samples not available.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check www.ti.com/productcontent for the latest
availability information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the
requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified
lead-free processes.
Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used
between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by
weight in homogeneous material).
(3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.
(4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device.
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(5) Multiple Device markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a
continuation of the previous line and the two combined represent the entire Device Marking for that device.
(6) Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the
finish value exceeds the maximum column width.
Important Information and Disclaimer: The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on
information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties.
TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming
materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.
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12.2 Tape and Reel Information
REEL DIMENSIONS
TAPE DIMENSIONS
K0
P1
W
B0
Reel
Diameter
Cavity
A0
A0 Dimension designed to accommodate the component width
B0 Dimension designed to accommodate the component length
K0 Dimension designed to accommodate the component thickness
Overall width of the carrier tape
W
P1 Pitch between successive cavity centers
Reel Width (W1)
QUADRANT ASSIGNMENTS FOR PIN 1 ORIENTATION IN TAPE
Sprocket Holes
Q1 Q2
Q3 Q4
Q1 Q2
Q3 Q4
User Direction of Feed
Pocket Quadrants
Reel
Diameter
(mm)
Reel
Width W1
(mm)
Package
Type
Package
Drawing
A0
(mm)
B0
(mm)
K0
(mm)
P1
(mm)
W
(mm)
Pin1
Quadrant
Device
Pins
SPQ
PHDC3020DEFT
PHDC3021DEFT
PHDC3022DEFT
HDC3020DEFR
HDC3020DEFT
HDC3021DEHR
HDC3021DEHT
HDC3022DEJR
HDC3022DEJT
WSON
WSON
WSON
WSON
WSON
WSON
WSON
WSON
WSON
DEF
DEH
DEJ
DEF
DEF
DEH
DEH
DEJ
DEJ
8
8
8
8
8
8
8
8
8
250
250
178
178
178
60
12
12
12
12
12
12
12
12
12
2.75
2.75
2.75
2.75
2.75
2.8
2.75
2.75
2.75
2.75
2.75
2.8
1.3
1.3
1.3
1.3
1.3
1.1
1.1
1.3
1.3
8
8
8
8
8
8
8
8
8
12
12
12
12
12
12
12
12
12
2
2
2
2
2
2
2
2
2
250
3000
250
178
60
3000
250
178
60
2.8
2.8
3000
250
2.75
2.75
2.75
2.75
178
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TAPE AND REEL BOX DIMENSIONS
Width (mm)
H
W
L
Device
Package Type
WSON
Package Drawing Pins
SPQ
250
Length (mm) Width (mm)
Height (mm)
PHDC3020DEFT
DEF
DEF
DEF
DEF
DEF
DEH
DEH
DEJ
DEJ
8
8
8
8
8
8
8
8
8
193
193
193
193
193
193
193
193
193
193
193
193
193
193
193
193
193
193
70
70
70
70
70
70
70
70
70
PHDC3021DEFT
PHDC3022DEFT
HDC3020DEFR
HDC3020DEFT
HDC3021DEHR
HDC3021DEHT
HDC3022DEJR
HDC3022DEJT
WSON
250
WSON
250
WSON
3000
250
WSON
WSON
3000
250
WSON
WSON
3000
250
WSON
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PACKAGE OPTION ADDENDUM
www.ti.com
18-Jun-2021
PACKAGING INFORMATION
Orderable Device
Status Package Type Package Pins Package
Eco Plan
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
Samples
Drawing
Qty
(1)
(2)
(3)
(4/5)
(6)
PHDC3020DEFT
ACTIVE
WSON
DEF
8
250
Non-RoHS &
Non-Green
Call TI
Call TI
-40 to 125
(1) The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of <=1000ppm threshold. Antimony trioxide based
flame retardants must also meet the <=1000ppm threshold requirement.
(3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.
(4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device.
(5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation
of the previous line and the two combined represent the entire Device Marking for that device.
(6)
Lead finish/Ball material - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead finish/Ball material values may wrap to two
lines if the finish value exceeds the maximum column width.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information
provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and
continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.
TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.
Addendum-Page 1
PACKAGE OPTION ADDENDUM
www.ti.com
18-Jun-2021
OTHER QUALIFIED VERSIONS OF HDC3020 :
Automotive : HDC3020-Q1
•
NOTE: Qualified Version Definitions:
Automotive - Q100 devices qualified for high-reliability automotive applications targeting zero defects
•
Addendum-Page 2
IMPORTANT NOTICE AND DISCLAIMER
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IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT OF THIRD
PARTY INTELLECTUAL PROPERTY RIGHTS.
These resources are intended for skilled developers designing with TI products. You are solely responsible for (1) selecting the appropriate
TI products for your application, (2) designing, validating and testing your application, and (3) ensuring your application meets applicable
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Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265
Copyright © 2021, Texas Instruments Incorporated
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