Si7005
D
IGITA L
I
2
C H
UMIDITY AND
T
EMPERATURE
S
ENSOR
Features
Relative Humidity Sensor
±
4.5 % RH (maximum @ 0–80% RH)
Temperature Sensor
±0.5
ºC accuracy (typical)
±1 ºC accuracy (maximum @ 0 to 70 °C)
0 to 100% RH operating range
–40 to +85 °C (GM) or 0 to +70 °C
operating range (FM)
Wide operating voltage range
(2.1 to 3.6 V)
Low Power Consumption
240
I
2
C host interface
Integrated on-chip heater
4x4 mm QFN package
Excellent long term stability
Factory calibrated
Optional factory-installed
cover
Low-profile
Protection
µA during RH conversion
during reflow
Excludes liquids and
particulates
(hydrophobic/oleophobic)
Ordering Information
See Ordering Guide.
Patent protected; patents pending
Applications
Industrial HVAC/R
Thermostats/humidistats
Respiratory therapy
White goods
Micro-environments/data centers
Automotive climate control and
de-fogging
Asset and goods tracking
GND
1
2
3
4
5
6
DNC
SCL
Pin Assignments
GND
19
18 DNC
17 DNC
16 DNC
15 CS
14 DNC
13 DNC
10
11
GND
12
DNC
7
8
9
DNC
DNC
DNC
DNC
21
C
EXT
DNC
20
24
23
GND
Description
The Si7005 is a digital relative humidity and temperature sensor. This
monolithic CMOS IC integrates temperature and humidity sensor
elements, an analog-to-digital converter, signal processing, calibration
data, and an I
2
C host interface. The patented use of industry-standard,
low-K polymeric dielectrics for sensing humidity enables the construction
of a low-power, monolithic CMOS sensor IC with low drift and hysteresis
and excellent long term stability.
Both the temperature and humidity 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 Si7005 is packaged in a 4x4 mm QFN package and is reflow
solderable. The optional factory-installed protective 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 Si7005 offers an accurate, low-power, factory-calibrated digital
solution ideal for measuring temperature, humidity, and dew-point in
applications ranging from HVAC/R and asset tracking to industrial and
consumer platforms.
SDA
DNC
DNC
DNC
Rev. 1.2 1/14
Copyright © 2014 by Silicon Laboratories
V
DD
22
Si7005
Si7005
Functional Block Diagram
V
DD
I
2
C pullups may be
integrated in microcontroller
R = 10 k (typ)
V
DD
C = 0.1 µF
V
DD
CEXT
NV CAL
Humidity
Sensor
MUX
Temperature
Sensor
GND
32 kHz Osc
Logic
I
2
C
Serial
IF
SCL
SDA
CS
R = 10 k (typ)
C = 4.7 µF
PXx
PXy
PXz
Microcontroller
ADC
Si7005
2
Rev. 1.2
Si7005
T
ABLE O F
C
ONTENTS
Section
Page
1. Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
2. Typical Application Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3. Bill of Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4. Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.2. Relative Humidity Sensor Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.3. Linearization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
4.4. Temperature Compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.5. Hysteresis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.6. Prolonged Exposure to High Humidity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.7. PCB Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.8. Protecting the Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.9. Bake/Hydrate Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.10. Long Term Drift/Aging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
5. Host Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
5.1. I
2
C Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
5.2. I
2
C Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
6. Si7005 Connection Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
7. Control Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
7.1. Register Detail (Defaults in Bold) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
8. Pin Descriptions: Si7005 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
9. Ordering Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
10. Package Outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
10.1. 24-Pin QFN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
10.2. 24-Pin QFN with Protective Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
11. PCB Land Pattern and Solder Mask Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
12. Top Marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36
12.1. Si7005 Top Marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
12.2. Top Marking Explanation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
13. Additional Reference Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Document Change List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38
Contact Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40
Rev. 1.2
3
Si7005
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
Operating Temperature
Symbol
V
DD
T
A
T
A
G grade
F grade
Test Condition
Min
2.1
–40
0
Typ
3.3
—
—
Max
3.6
85
70
Unit
V
°C
°C
Table 2. General Specifications
2.1
V
DD
3.6 V; T
A
= 0 to 70 °C (F grade) or –40 to 85 °C (G grade) unless otherwise noted.
Parameter
Input Voltage High
Input Voltage Low
Input Voltage Range
Symbol
V
IH
V
IL
V
IN
Test Condition
CS, SCL, SDA pins
CS, SCL, SDA pins
SCL, SDA pins with respect
to GND
CS, C
EXT
pin with respect to
GND
Min
0.7xV
DD
—
0.0
0.0
—
—
—
Typ
—
—
—
—
—
—
—
Max
—
0.3xV
DD
3.6
V
DD
±1
0.6
0.4
Unit
V
V
V
V
µA
V
V
Input Leakage
Output Voltage Low
I
IL
V
OL
CS, SCL, SDA pins
SDA pin; I
OL
= 8.5 mA;
V
DD
= 3.3 V
SDA pin; I
OL
= 3.5 mA;
V
DD
= 2.1 V
Notes:
1.
Si7005 can draw excess current if V
DD
and CS are ramped high together. To enter the lowest power mode, either hold
CS low while V
DD
ramps or pulse CS low after V
DD
reaches its final value.
2.
SDA and SCL pins have an internal 75 k pull-up resistor to VDD
4
Rev. 1.2
Si7005
Table 2. General Specifications (Continued)
2.1
V
DD
3.6 V; T
A
= 0 to 70 °C (F grade) or –40 to 85 °C (G grade) unless otherwise noted.
Parameter
Power Consumption
Symbol
I
DD
Test Condition
RH conversion in progress
Temperature conversion in
progress
Average for 1 temperature
and 1 RH conversion /
minute
CS < V
IL
; no conversion in
progress; V
DD
= 3.3 V;
SDA = SCL
≥
V
IH
CS > V
IH
CS < V
IL
; no conversion in
progress; V
DD
= 3.3 V;
SDA = SCL
≥
V
IH
; HEAT = 1
Min
—
—
—
Typ
240
320
1
Max
560
565
—
Unit
µA
µA
µA
—
150
—
µA
—
—
—
24
100
31
µA
mA
Conversion Time
t
CONV
14-bit temperature; 12-bit RH
(Fast = 0)
13-bit temperature; 11-bit RH
(Fast = 1)
35
18
10
10
40
ms
21
15
15
ms
ms
Wake Up Time
Power Up Time
t
CS
t
PU
From CS < VIL to ready for a
temp/RH conversion
From V
DD
≥
2.1V to ready for
a temp/RH conversion
Notes:
1.
Si7005 can draw excess current if V
DD
and CS are ramped high together. To enter the lowest power mode, either hold
CS low while V
DD
ramps or pulse CS low after V
DD
reaches its final value.
2.
SDA and SCL pins have an internal 75 k pull-up resistor to VDD
Rev. 1.2
5
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