S i7022- A2 0
H
U M I D I T Y
/T
E M P E R A T U R E
S
E N S O R
Features
WITH
PWM O
U T P U T
Precision Relative Humidity Sensor
± 4% RH (max), 0–80% RH
High Accuracy Temperature Sensor
±0.4 °C (max), –10 to 85 °C
0 to 100% RH operating range
–40 to +125 °C operating range
Wide operating voltage
(1.9 to 3.6 V)
Low Power Consumption
Factory-calibrated
PWM Output
3x3 mm DFN Package
Excellent long term stability
Optional factory-installed cover
Low-profile
Protection during reflow
Excludes liquids and particulates
Applications
HVAC/R
Thermostats/humidistats
Respiratory therapy
White goods
Indoor weather stations
Micro-environments/data centers
Automotive climate control and
defogging
Asset and goods tracking
Mobile phones and tablets
Ordering Information:
See page 18.
Pin Assignments
Description
The Si7022 Humidity and Temperature Sensor is a monolithic CMOS IC
integrating humidity and temperature sensor elements, an analog-to-digital
converter, signal processing, calibration data, and a PWM output. The PWM
output may be filtered to produce an analog voltage output. The patented use of
industry-standard, low-K polymeric dielectrics for sensing humidity enables the
construction of low-power, monolithic CMOS Sensor ICs with low drift and
hysteresis, and excellent long term stability.
The humidity and temperature sensors are factory-calibrated and the calibration
data is stored in the on-chip non-volatile memory. This ensures that the sensors
are fully interchangeable, with no recalibration or software changes required.
The Si7022 is available in a 3x3 mm DFN package and is reflow solderable. It can
be used as a hardware- and software-compatible drop-in upgrade for existing RH/
temperature sensors in 3x3 mm DFN-6 packages, featuring precision sensing
over a wider range and lower power consumption. The optional factory-installed
cover offers a low profile, convenient means of protecting the sensor during
assembly (e.g., reflow soldering) and throughout the life of the product, excluding
liquids (hydrophobic/oleophobic) and particulates.
The Si7022 offers an accurate, low-power, factory-calibrated digital solution ideal
for measuring humidity, dew-point, and temperature, in applications ranging from
HVAC/R and asset tracking to industrial and consumer platforms.
Top View
Patent Protected. Patents pending
Rev. 1.1 6/15
Copyright © 2015 by Silicon Laboratories
Si7022-A20
Si7022- A20
Functional Block Diagram
2
Rev. 1.1
Si7022-A 20
T
A B L E
Section
OF
C
ONTENTS
Page
1. Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
2. Typical Application Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
3. Bill of Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
4. Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
4.1. Relative Humidity Sensor Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
4.2. Hysteresis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
4.3. Prolonged Exposure to High Humidity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
4.4. PCB Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
4.5. Protecting the Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
4.6. Bake/Hydrate Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
4.7. Long Term Drift/Aging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
5. PWM Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
6. Pin Descriptions: Si7022 (Top View) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
7. Ordering Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
8. Package Outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
8.1. Package Outline: 3x3 6-pin DFN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
8.2. Package Outline: 3x3 6-pin DFN with Protective Cover . . . . . . . . . . . . . . . . . . . . . .20
9. PCB Land Pattern and Solder Mask Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
10. Top Marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
10.1. Si7022 Top Marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
10.2. Top Marking Explanation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
11. Additional Reference Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Document Change List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Contact Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Rev. 1.1
3
Si7022- A20
1. Electrical Specifications
Unless otherwise specified, all min/max specifications apply over the recommended operating conditions.
Table 1. Recommended Operating Conditions
Parameter
Power Supply
Operating Temperature
Symbol
V
DD
T
A
Test Condition
Min
1.9
–40
Typ
—
—
Max
3.6
+125
Unit
V
°C
Table 2. General Specifications
1.9 < V
DD
< 3.6 V; T
A
= –40 to 125 °C unless otherwise noted.
Parameter
Input Voltage High
Input Voltage Low
Input Voltage Range
Input Leakage
Output Voltage High
Symbol
V
IH
V
IL
V
IN
I
IL
V
OH
Test Condition
SELECT pin
SELECT pin
SELECT pin with respect to GND
SELECT pin
PWM1, PWM2 pins, IOH = –10
μA
PWM1, PWM2 pins pin,
IOH = –0.5 mA, V
DD
= 2.0 V
PWM1, PWM2 pins,
IOH = –1.7 mA, V
DD
= 3.0 V
Min
0.7xV
DD
—
0.0
—
V
DD
– 0.1
V
DD
– 0.2
V
DD
– 0.4
—
—
—
—
—
—
Typ
—
—
—
—
—
—
—
—
—
2
150
48
—
Max
—
0.3xV
DD
V
DD
1
—
—
—
0.6
0.4
—
300
55
110
Unit
V
V
V
μA
V
Output Voltage Low
V
OL
PWM1, PWM2 pins; I
OL
= 2.5 mA;
V
DD
= 3.3 V
PWM1, PWM2 pins; I
OL
= 1.2 mA;
V
DD
= 1.9 V
V
V
Hz
μA
Sample Rate
Current
Consumption
Powerup Time
I
DD
t
PU
RH and Temperature
Average Current
From V
DD
≥
1.9 V to PWM output
enabled, 25 °C
From V
DD
≥
1.9 V to PWM output
enabled, full temperature range
ms
4
Rev. 1.1
Si7022-A 20
Table 3. PWM Interface Specifications
1.9
V
DD
3.6 V; T
A
= –40 to +125 °C unless otherwise noted.
Parameter
PWM Frequency
PWM Duty Cycle
SELECT Setup Time
Symbol
F
PWM
DC
PWM
t
SS
Test Condition
Min
1.00
Typ
1.22
—
500
Max
1.40
100
—
Unit
kHz
%
ms
t
H
/ t
PWM
From SELECT transition to
PWM valid
0
—
Figure 1. PWM Interface Timing Diagram
Rev. 1.1
5
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