Si7015-A20 Digital I2C Humidity and Temperature Sensor

Si 7 0 1 5 - A20
D IGITA L I 2 C H UMIDITY AND TEMPERATURE S ENSOR
Features


Precision Relative Humidity Sensor

±

4.5% RH (max), 0–80% RH
High-Accuracy Temperature Sensor
±1





ºC (max), –10 to 85 °C


0 to 100% RH operating range

0 to +70 °C operating range (FM)

–40 to +85 °C operating range (GM)

Low Voltage Operation (1.9 to 3.6 V)
Low Power Consumption
150
µA active current
60 nA standby current
Drop-In Upgrade for Si7005
Factory-calibrated
I2C Interface
Integrated on-chip heater
4x4 mm QFN package
Excellent long term stability
Optional factory-installed
cover
Low-profile
during reflow
Excludes liquids and
particulates
Ordering Information
Protection
See page 31.
Patent protected; patents pending
Applications
DNC
DNC
DNC
DNC
DNC
GND
22
21
20
19
18 DNC
2
17 DNC
SCL
3
16 DNC
12
DNC
13 DNC
11
DNC
GND
14 DNC
6
10
15 CS
5
DNC
4
9
SDA
DNC
VDD
The Si7015 I C Humidity and Temperature Sensor is a monolithic CMOS
IC integrating humidity and temperature sensor elements, an analog-todigital converter, signal processing, calibration data, and an I2C Interface.
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.
1
DNC
8
2
GND
7
Description
23
Micro-environments/data centers
 Industrial controls
 Weather stations
 Asset tracking and storage
24
Pin Assignments

DNC
HVAC/R
 Thermostats/humidistats
 Instrumentation
 White goods
GND

Each unit is factory-calibrated, and the calibration data is stored in the onchip non-volatile memory. This ensures that the sensors are fully
interchangeable, with no recalibration or software changes required. The
Si7015 can be used as a drop-in upgrade for the Si7005 with only minor
software changes because the register sets are the same, and the
4x4 mm QFN package is footprint-compatible with that of the Si7005.
The device is compatible with standard SMT assembly processes, such
as reflow. The optional factory-installed cover offers a low profile and
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 Si7015 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.
Rev. 1.1 2/16
Copyright © 2016 by Silicon Laboratories
Si7015-A20
Si7015-A20
Functional Block Diagram
2
Rev. 1.1
Si7015-A20
TABLE O F C ONTENTS
Section
Page
1. Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
2. Typical Application Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
3. Bill of Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4. Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.2. Relative Humidity Sensor Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.3. Temperature Compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
4.4. Hysteresis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
4.5. Prolonged Exposure to High Humidity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
4.6. PCB Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
4.7. Protecting the Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.8. Bake/Hydrate Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.9. Long Term Drift/Aging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5. Host Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
5.1. I2C Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
5.2. I2C Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
6. Control Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
6.1. Register Detail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
7. Pin Descriptions: Si7015 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
8. Ordering Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
9. Package Outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
9.1. 24-Pin QFN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
9.2. 24-Pin QFN with Protective Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
10. PCB Land Pattern and Solder Mask Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
11. Top Marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36
11.1. Si7015 Top Marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
11.2. Top Marking Explanation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
12. Additional Reference Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Document Change List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38
Contact Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39
Rev. 1.1
3
Si7015-A20
1. Electrical Specifications
Unless otherwise specified, all min/max specifications apply over the recommended operating conditions.
Table 1. Recommended Operating Conditions
Parameter
Symbol
Power Supply
Test Condition
VDD
Min
Typ
Max
Unit
1.9
—
3.6
V
Operating Temperature
TA
F grade
0
—
+70
°C
Operating Temperature
TA
G grade
–40
—
+85
°C
Table 2. General Specifications
1.9 < VDD < 3.6 V; TA = –40 to 85 °C (G grade) or 0 to 70 °C (F grade); default conversion time unless otherwise noted.
Parameter
Symbol
Test Condition1
Min
Typ
Max
Unit
Input Voltage High
VIH
AD0, SCL, SDA pins
0.7xVDD
—
—
V
Input Voltage Low
VIL
AD0, SCL, SDA pins
—
—
0.3xVDD
V
Input Voltage Range
VIN
SCL, SDA, RSTb pins with respect to
GND
0.0
—
VDD
V
Input Leakage
IIL
SCL, SDA pins; VIN = GND
—
—
1
μA
CS pin (200K nominal pull up);
Vin = GND
Output Voltage Low
Current
Consumption
VOL
IDD
SDA pin; IOL = 2.5 mA; VDD = 3.3 V
—
—
0.6
V
SDA pin; IOL = 1.2 mA;
VDD = 1.9 V
—
—
0.4
V
RH conversion in progress
—
150
180
µA
Temperature conversion in progress
—
90
120
µA
CS < VIL; no conversion in progress;
VDD = 3.3 V;
SDA = SCL ≥ VIH; HEAT = 1
—
24
—
Standby2, –40 to +85°C
—
0.06
0.62
µA
—
3.5
4.0
mA
—
3.5
4.0
mA
RH Normal (Fast = 0)
—
5.8
7.0
ms
RH Fast (Fast = 1)
—
2.6
3.1
ms
Temperature Normal (Fast = 0)
—
4.0
6.2
ms
Temperature Fast (Fast = 1)
—
1.5
2.4
ms
Peak IDD during powerup
Peak IDD during
Conversion Time
tCONV
μA
5xVDD
I2C
3
operations4
mA
Notes:
1. Initiating a RH measurement will also automatically initiate a temperature measurement. The total conversion time will
be tCONV(RH) + tCONV(T).
2. No conversion or I2C transaction in progress. Typical values measured at 25 °C.
3. Occurs once during powerup. Duration is <5 msec.
4. Occurs during I2C commands for Read Device ID and Read Firmware Version. Duration is < 100 µs when I2C clock
speed is >100 kHz.
4
Rev. 1.1
Si7015-A20
Table 2. General Specifications (Continued)
1.9 < VDD < 3.6 V; TA = –40 to 85 °C (G grade) or 0 to 70 °C (F grade); default conversion time unless otherwise noted.
Parameter
Symbol
Test Condition1
Min
Typ
Max
Unit
Wake Up Time
tCS
From CS < VIL to ready for a temp/RH
conversion
—
—
1
ms
Power Up Time
tPU
From VDD ≥ 1.9 V to ready for a temp/
RH conversion, 25°C
—
18
25
ms
From VDD ≥ 1.9 V to ready for a temp/
RH conversion, full temperature range
—
—
80
ms
Notes:
1. Initiating a RH measurement will also automatically initiate a temperature measurement. The total conversion time will
be tCONV(RH) + tCONV(T).
2. No conversion or I2C transaction in progress. Typical values measured at 25 °C.
3. Occurs once during powerup. Duration is <5 msec.
4. Occurs during I2C commands for Read Device ID and Read Firmware Version. Duration is < 100 µs when I2C clock
speed is >100 kHz.
Table 3. I2C Interface Specifications1
1.9 VDD  3.6 V; TA = 0 to 70 °C (F grade) or –40 to +85 °C (G grade) unless otherwise noted.
Parameter
Symbol
Test Condition
Min
Typ
Max
Unit
Hysteresis
VHYS
High-to-low versus low-tohigh transition
0.05 x VDD
—
—
V
SCLK Frequency
fSCL
—
—
400
kHz
SCL High Time
tSKH
0.6
—
—
µs
SCL Low Time
tSKL
1.3
—
—
µs
Start Hold Time
tSTH
0.6
—
—
µs
Start Setup Time
tSTS
0.6
—
—
µs
Stop Setup Time
tSPS
0.6
—
—
µs
Bus Free Time
tBUF
1.3
—
—
µs
SDA Setup Time
tDS
100
—
—
ns
SDA Hold Time
tDH
100
—
—
ns
SDA Valid Time
tVD;DAT
From SCL low to data valid
—
—
0.9
µs
SDA Acknowledge Valid Time
tVD;ACK
From SCL low to data valid
—
—
0.9
µs
50
—
—
ns
Suppressed Pulse Width2
Between Stop and Start
tSP
Notes:
1. All values are referenced to VIL and/or VIH.
2. Pulses up to and including 50ns will be suppressed.
Rev. 1.1
5
Si7015-A20
tSKH
1/fSCL
tSKL
tSP
SCL
tBUF
tSTH
tDS
D6
SDA
D5
tDH
D4
D0
tSPS
R/W
ACK
Start Bit
Stop Bit
tVD : ACK
tSTS
Figure 1. I2C Interface Timing Diagram
6
Rev. 1.1
Si7015-A20
Table 4. Humidity Sensor
1.9 ≤ VDD ≤ 3.6 V; TA = 30 °C; default conversion time unless otherwise noted.
Parameter
Symbol
1
Operating Range
Accuracy2, 3
Test Condition
Min
Typ
Max
Unit
Non-condensing
0
—
100
%RH
0 – 80% RH
—
±3.0
±4.5
%RH
80 – 100% RH
Repeatability/Noise
See Figure 2.
%RH
Normal Mode
—
0.05
—
%RH RMS
Fast Mode
—
0.2
—
%RH RMS
1 m/s airflow, with cover
—
18
—
1 m/s airflow, without cover
—
17
—
Drift vs. Temperature
—
0.05
—
%RH/°C
Hysteresis
—
±1
—
%RH
Long Term Stability3
—
< 0.25
—
%RH/yr
Response Time4
τ63%
S
Notes:
1. Recommended humidity operating range is 20% to 80% RH (non-condensing) over –10 °C to 60 °C.
Prolonged operation beyond these ranges may result in a shift of sensor reading with slow recovery time.
2. Excludes hysteresis, long term drift, and certain other factors and is applicable to non-condensing environments only.
See Section “4.2. Relative Humidity Sensor Accuracy” for more details.
3. Drift due to aging effects at typical room conditions of 30C and 30% to 50%. May be impacted by dust, vaporized
solvents or other contaminants, e.g., out-gassing tapes, adhesives, packaging materials, etc. See Section “4.9. Long
Term Drift/Aging”.
4. Response time to a step change in RH. Time for the RH output to change by 63% of the total RH change.
RHAccuracy
Max.RHError(±%)
Typ.RHError(±%)
10
RHMeasurementError(±%)
9
8
7
6
5
4
3
2
1
0
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
RelativeHumidity(%)
Figure 2. RH Accuracy at 30 °C
Rev. 1.1
7
Si7015-A20
Table 5. Temperature Sensor
1.9 ≤ VDD ≤ 3.6 V; TA = –40 to +85 °C (G grade) or 0 to +70 °C (F grade), default conversion time unless otherwise noted.
Parameter
Symbol
Operating Range
Accuracy1
Test Condition
Min
Typ
Max
Unit
F Grade
0
—
+70
°C
G Grade
–40
—
+85
°C
0 °C < tA < 70 °C
—
±0.5
±1.0
°C
–40 °C < tA < 85 °C
Repeatability/Noise
Response Time2
τ63%
Figure 3.
°C
Normal Mode
—
0.02
—
°C RMS
Fast Mode
—
0.08
—
°C RMS
Unmounted device
—
0.7
—
s
Si7015-EB board
—
5.1
—
s
—
< 0.01
—
Long Term Stability
°C/Yr
Notes:
1. 14b measurement resolution (default).
2. Time to reach 63% of final value in response to a step change in temperature. Actual response time will vary dependent
on system thermal mass and air-flow.
Figure 3. Temperature Accuracy*
Note: Figure 3 only applies to G-grade devices beyond 70C.
8
Rev. 1.1
Si7015-A20
Table 6. Thermal Characteristics
Symbol
Test Condition
QFN-24
Unit
Junction-to-Air Thermal Resistance
JA
JEDEC 4-layer board
55
°C/W
Junction-to-Air Thermal Resistance
JA
2-layer evaluation PCB with
minimal thermal pad
110
°C/W
Parameter
Table 7. Absolute Maximum Ratings1,2
Min
Typ
Max
Unit
Ambient Temperature under Bias
–55
—
125
°C
Storage Temperature
–65
—
150
°C
Voltage on SDA or SCL Pin with Respect
to GND
–0.3
—
VDD+ 0.3
V
Voltage on CS pin with Respect to GND
–0.3
—
VDD + 0.3
V
Voltage on VDD with Respect to GND
–0.3
—
4.2
V
HBM
—
—
2
kV
CDM
—
—
1.25
kV
MM
—
—
250
V
Parameter
Symbol
Test
Condition
ESD Tolerance
Notes:
1. Absolute maximum ratings are stress ratings only; operation at or beyond these conditions is not implied and may
shorten the life of the device or alter its performance.
2. Special handling considerations apply; see “AN607: Si70xx Humidity Sensor Designer’s Guide” for details.
Rev. 1.1
9
Si7015-A20
GND
19
20
DNC
21
DNC
22
23
DNC
DNC
DNC
Si7015
SDA
CS
DNC
DNC
17
16
15
14
13
12
7
18
DNC
DNC
GND
DNC
DNC
6
U3
SCL
11
5
DNC
DNC
4
DNC
VDD
3
DNC
10
SDA *
2
GND
GND
SCL *
R2
10K
9
1
R1
10K
8
VDD
DNC
EPAD
25
24
2. Typical Application Circuit
CSb
C1
0.1uF
GND
Figure 4. Typical Application Circuit*
*Note: If Si7015 is replacing an Si7005, the capacitor connected to Pin 10 may be left connected or removed.
10
Rev. 1.1
Si7015-A20
3. Bill of Materials
Table 8. Typical Application Circuit BOM*
Reference
Description
Mfr Part Number
Manufacturer
C1
Capacitor, 0.1 µF, 6.3 V, X7R, 0603
C0603X7R6R3-104M
Venkel
R1*
Resistor, 10 k, ±5%, 1/16 W, 0603
CR0603-16W-1002J
Venkel
R2*
Resistor, 10 k, ±5%, 1/16 W, 0603
CR0603-16W-1002J
Venkel
U1
IC, digital temperature/humidity sensor
Si7015-A20
Silicon Labs
*Note: Typical value shown. Optimal value depends on bus capacitance and speed of bus operation; not needed if present
elsewhere in the system.
Rev. 1.1
11
Si7015-A20
4. Functional Description
Figure 5. Si7015 Functional Block Diagram
4.1. Overview
The Si7015 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 I2C host
interface. Both the temperature and humidity sensors on each unit 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.
While the Si7015 is largely a conventional mixed-signal CMOS integrated circuit, relative humidity sensors in
general and those based on capacitive sensing using polymeric dielectric have unique application and use
requirements that are not common to conventional (non-sensor) ICs. Chief among those are:
The
need to protect the sensor during board assembly, i.e., solder reflow, and the need to subsequently
rehydrate the sensor.
The need to apply temperature correction to the humidity readings.
The need to protect the sensor from damage or contamination during the product life-cycle.
The impact of prolonged exposure to extremes of temperature and/or humidity and their potential effect on
sensor accuracy.
The effects of humidity sensor “memory”.
Each of these items is discussed in more detail in the following sections.
12
Rev. 1.1
Si7015-A20
4.2. Relative Humidity Sensor Accuracy
To determine the accuracy of a relative humidity sensor, it is placed in a temperature and humidity controlled
chamber. The temperature is set to a convenient fixed value (typically 30 °C) and the relative humidity is swept
from 20 to 80% and back to 20% in the following steps: 20% – 40% – 60% – 80% – 80% – 60% – 40% – 20%. At
each set-point, the chamber is allowed to settle for a period of 60 minutes before a reading is taken from the
sensor. Prior to the sweep, the device is allowed to stabilize to 50%RH. The solid top and bottom trace in Figure 6,
“Measuring Sensor Accuracy Including Hysteresis,” shows the result of a typical sweep after non-linearity
compensation.
RHAccuracyvs.RHSetͲPoint
5
4
Hysteresis
3
%RHAccuracy
2
1
0
Ͳ1
10
20
30
40
50
60
70
80
90
Ͳ2
Ͳ3
Ͳ4
Ͳ5
%RHSetͲpoint
Figure 6. Measuring Sensor Accuracy Including Hysteresis
The RH accuracy is defined as the center (dashed) line shown in Figure 6, which is the average of the two data
points at each relative humidity set-point. In this case, the sensor shows an accuracy of 0.25%RH. The Si7015
accuracy specification (Table 4) includes the following:
Unit-to-unit
and lot-to-lot variation in non-linearity compensation
of factory calibration
Margin for shifts that can occur during solder reflow.
The accuracy specification does not include the following:
Accuracy
Hysteresis
(typically ±1%)
Effects from long term exposure to very humid conditions
Contamination of the sensor by particulates, chemicals, etc.
Other aging related shifts (“Long-term stability”)
Variations due to temperature
Rev. 1.1
13
Si7015-A20
4.3. Temperature Compensation
The Si7015 relative humidity sensor is calibrated at a temperature of 30 °C; it is at this temperature that the sensor
will give the most accurate relative humidity readings. For relative humidity measurements at other temperatures,
the RH reading from the Si7015 must be compensated for the change in temperature relative to 30 °C.
Temperature-compensated relative humidity readings can be calculated as follows:
RH TempCompensated = RH Linear +  Temperature – 30    RH Linear  Q 1 + Q 0 
Where:
RHTempCompensated
RHLinear
is the temperature compensated relative humidity value in %RH.
is the linear corrected relative humidity value in %RH.
Temperature
is the ambient temperature in °C as measured by the Si7015 on chip temperature sensor.
and Q0 are unit-less correction coefficients derived through characterization of Si7015s by Silicon
Laboratories.
This temperature compensation is most accurate in the range of 15–50 °C. The values for the correction
coefficients are shown in Table 9.
Q1
Table 9. Linearization Coefficients
Coefficient
Value
Q0
0.060162
Q1
0.000508
4.4. Hysteresis
The moisture absorbent film (polymeric dielectric) of the humidity sensor will carry a memory of its exposure
history, particularly its recent or extreme exposure history. A sensor exposed to relatively low humidity will carry a
negative offset relative to the factory calibration, and a sensor exposed to relatively high humidity will carry a
positive offset relative to the factory calibration. This factor causes a hysteresis effect illustrated by the solid top
and bottom traces in Figure 6. The hysteresis value is the difference in %RH between the maximum absolute error
on the decreasing humidity ramp and the maximum absolute error on the increasing humidity ramp at a single
relative humidity Setpoint and is expressed as a bipolar quantity relative to the average, the center dashed trace in
Figure 6. In the case of Figure 6, the measurement uncertainty due to the hysteresis effect is ±1.05%RH.
4.5. Prolonged Exposure to High Humidity
Prolonged exposure to high humidity will result in a gradual upward drift of the RH reading. The shift in sensor
reading resulting from this drift will generally disappear slowly under normal ambient conditions. The amount of
shift is proportional to the magnitude of relative humidity and the length of exposure. In the case of lengthy
exposure to high humidity, some of the resulting shift may persist indefinitely under typical conditions. It is generally
possible to substantially reverse this affect by baking the device (see Section “4.8. Bake/Hydrate Procedure”).
14
Rev. 1.1
Si7015-A20
4.6. PCB Assembly
4.6.1. Soldering
Like most ICs, Si7015 devices are shipped from the factory vacuum-packed with an enclosed desiccant to avoid
any drift during storage and to prevent any moisture-related issues during solder reflow. The following guidelines
should be observed during PCB assembly:
Si7015
devices are compatible with standard board assembly processes. Devices should be soldered
using reflow per the recommended card reflow profile. See Section “10. PCB Land Pattern and Solder
Mask Design” for the recommended card reflow profile.
A “no clean” solder process is recommended to minimize the need for water or solvent rinses after
soldering. Cleaning after soldering is possible, but must be done carefully to avoid impacting the
performance of the sensor. See application note, “AN607: Si70xx Humidity Sensor Designer’s Guide” for
more information on cleaning.
It is essential that the exposed polymer sensing film be kept clean and undamaged. This can be
accomplished by careful handling and a clean, well-controlled assembly process. When in doubt or for
extra protection, a heat-resistant, protective cover such as Kapton® KPPD-1/8 can be installed during PCB
assembly.
Si7015s may be ordered with a factory-fitted, solder-resistant protective cover. This cover provides protection
during PCB assembly or rework but without the time and effort required to install and remove the Kapton® tape. It
can be left in place for the lifetime of the product, preventing liquids, dust, or other contaminants from coming into
contact with the polymer sensor film. See Section “8. Ordering Guide” for a list of ordering part numbers that
include the cover.
4.6.2. Rehydration
The measured humidity value will generally shift slightly after solder reflow. A portion of this shift is permanent and
is accounted for in the accuracy specifications in Table 4. After soldering, an Si7015 should be allowed to
equilibrate under controlled RH conditions (room temperature, 45-55%RH) for at least 48 hours to eliminate the
remainder of the shift and return the device to its specified accuracy performance.
Rev. 1.1
15
Si7015-A20
4.6.3. Rework
To maintain the specified sensor performance, care must be taken during rework to minimize the exposure of the
device to excessive heat and to avoid damage/contamination or a shift in the sensor reading due to liquids, solder
flux, etc. Manual touch-up using a soldering iron is permissible under the following guidelines:
The
exposed polymer sensing film must be kept clean and undamaged. A protective cover is
recommended during any rework operation (Kapton® tape or the factory-installed cover).
Flux must not be allowed to contaminate the sensor; liquid flux is not recommended even with a cover in
place. Conventional lead-free solder with rosin core is acceptable for touch-up as long as a cover is in
place during the rework.
If possible, avoid water or solvent rinses after touch-up. Cleaning after soldering is possible, but must be
done carefully to avoid impacting the performance of the sensor. See application note, “AN607: Si70xx
Humidity Sensor Designer’s Guide” for more information on cleaning.
Minimize the heating of the device. Soldering iron temperature should not exceed 350 °C and the contact
time per pin should not exceed five seconds.
Hot air rework is not recommended. If a device must be replaced, remove the device by hot air and solder
a new part in its place by reflow following the guidelines above.
*Note: All trademarks are the property of their respective owners.
Figure 7. Si7015 with Factory-Installed Protective Cover
16
Rev. 1.1
Si7015-A20
4.7. Protecting the Sensor
Because the sensor operates on the principal of measuring a change in capacitance, any changes to the dielectric
constant of the polymer film will be detected as a change in relative humidity. Therefore, it is important to minimize
the probability of contaminants coming into contact with the sensor. Dust and other particles as well as liquids can
affect the RH reading. It is recommended that a cover is employed in the end system that blocks contaminants but
allows water vapor to pass through. Depending on the needs of the application, this can be as simple as plastic or
metallic gauze for basic protection against particulates or something more sophisticated such as a hydrophobic
membrane providing up to IP67 compliant protection.
The Si7015 may be ordered with a factory-fitted, solder-resistant cover that can be left in place for the lifetime of
the product. It is very low-profile, hydrophobic and oleophobic. See Section “8. Ordering Guide” for a list of ordering
part numbers that include the cover. A dimensioned drawing of the IC with the cover is included in Section “9.
Package Outline”. Other characteristics of the cover are listed in Table 10.
Table 10. Specifications of Protective Cover
Parameter
Material
Value
PTFE
Operating Temperature
–40 to +125 °C
Maximum Reflow Temperature
IP Rating (per IEC 529)
260 °C
IP67
4.8. Bake/Hydrate Procedure
After exposure to extremes of temperature and/or humidity for prolonged periods, the polymer sensor film can
become either very dry or very wet; in each case the result is either high or low relative humidity readings. Under
normal operating conditions, the induced error will diminish over time. From a very dry condition, such as after
shipment and soldering, the error will diminish over a few days at typical controlled ambient conditions, e.g.,
48 hours of 45 ≤ %RH ≤ 55. However, from a very wet condition, recovery may take significantly longer. To
accelerate recovery from a wet condition, a bake and hydrate cycle can be implemented. This operation consists of
the following steps:
the sensor at 125 °C for ≥ 12 hours
at 30 °C in 75 %RH for ≥ 10 hours
Following this cycle, the sensor will return to normal operation in typical ambient conditions after a few days.
Baking
Hydration
4.9. Long Term Drift/Aging
Over long periods of time, the sensor readings may drift due to aging of the device. Standard accelerated life
testing of the Si7015 has resulted in the specifications for long-term drift shown in Table 4 and Table 5. This
contribution to the overall sensor accuracy accounts only for the long-term aging of the device in an otherwise
benign operating environment and does not include the affects of damage, contamination, or exposure to extreme
environmental conditions.
Rev. 1.1
17
Si7015-A20
5. Host Interface
5.1. I2C Interface
The Si7015 has an I2C serial interface with a 7-bit address of 0x40. The Si7015 is a slave device supporting data
transfer rates up to 400 kHz. Table 20 shows the register summary of the Si7015.
5.1.1. Performing a Relative Humidity Measurement
The following steps should be performed in sequence to take a relative humidity measurement:
1. Set START (D0) in CONFIG to begin a new conversion.
2. Poll RDY (D0) in STATUS (register 0) until it is low (= 0). (This must be done at least once prior to reading
results even if the host waits longer than tCONV.)
3. Read the upper and lower bytes of the RH value from DATAh and DATAl (registers 0x01 and 0x02),
respectively. Table 11 shows the format of the 12-bit relative humidity result.
4. Convert the RH value to %RH using the following equation:
RH
%RH =  --------- – 24
16
where RH is the measured value returned in DATAh:DATAI.
5. Apply temperature compensation as discussed elsewhere in this data sheet.
Due to normal variations in RH accuracy of the device as described in Table 4, it is possible for the measured value
of %RH to be slightly less than 0 when the actual RH level is close to or equal to 0. Similarly, the measured value
of %RH may be slightly greater than 100 when the actual RH level is close to or equal to 100. This is expected
behavior, and it is acceptable to limit the range of RH results to 0 to 100%RH in the host software by truncating
values that are slightly outside of this range.
Table 12 shows the 12-bit values that correspond to various measured RH levels.
Table 11. 12-Bit Relative Humidity Result Available in Registers 1 and 2
DATAh
D7
D6
D5
D4
D3
DATAI
D2
D1
D0
D7
12-Bit Relative Humidity Code
18
Rev. 1.1
D6
D5
D4
D3
D2
D1
D0
Si7015-A20
Table 12. Typical %RH Measurement Codes for 0 to 100% RH Range
%RH
12 Bit Code
Dec
Hex
0
384
180
10
544
220
20
704
2C0
30
864
360
40
1024
400
50
1184
4A0
60
1344
540
70
1504
5E0
80
1664
680
90
1824
720
100
1984
7C0
The above sequence assumes normal mode, i.e., tCONV = 5.8 ms (typical). Conversions may be performed in fast
mode. See Section “5.1.4. Fast Conversion Mode”.
Rev. 1.1
19
Si7015-A20
5.1.2. Performing a Temperature Measurement
The following steps should be performed in sequence to take a temperature measurement:
1. Set START (D0) and TEMP (D4) in CONFIG (register 0x03) to begin a new conversion, i.e., write CONFIG
with 0x11
2. Poll RDY (D0) in STATUS (register 0) until it is low (=0). This must be done at least once prior to reading
results even if the host waits longer than tCONV.
3. Read the upper and lower bytes of the temperature value from DATAh and DATAl (registers 0x01 and
0x02), respectively
Table 13 shows the format of the 14-bit temperature result. This value may be converted to °C using the following
equation:
TEMP
Temperature  C  =  ----------------- – 50
 32 
where TEMP is the measured value returned in DATAh:DATAI.
Table 14 shows the 14-bit values that correspond to various measured temperature levels.
Table 13. 14-Bit Temperature Result Available in Registers 1 and 2
DATAh
D7
D6
D5
D4
D3
DATAI
D2
D1
D0
D7
D6
D5
D4
D3
D2
D1
D0
14-Bit Temperature Code
The above sequence assumes normal mode, i.e., tCONV = 5.8 ms (typical). Conversions may be performed in fast
mode. See Section “5.1.4. Fast Conversion Mode”.
5.1.3. Entering Low-Power Mode
Either of the following sequences can be used to place the Si7015 into its low-power standby mode following an
RH conversion:
Option A:
Bring CSb high. This puts the Si7015 in low-power mode and disables I2C communication. This is similar to Si7005
except that the response to CSb high takes only a few usec and the VDD current is <1 µA (as opposed to Si7005
which can take >1second and can have VDD current of up to 100 µA).
Option B:
1. Poll /RDY until it returns zero, indicating that the conversion is finished.
2. Read the results of the RH conversion from DATAh:DATAl.
3. Clear the start bit (START) by writing 0x0 to register 3.
4. Clear the start bit (START) a second time by again writing 0x0 to register 3.
The Si7015 does enter its low-power standby mode following a temperature conversion. No action is required in
this case. However, please note that doing a temperature conversion following an RH conversion will not put the
Si7015 in low power state.
20
Rev. 1.1
Si7015-A20
Table 14. Typical Temperature Measurement Codes for the –40 °C to 100 °C Range
Temp(°C)
14 Bit Code
Dec
Hex
–40
320
0140
–30
640
0280
–20
960
03C0
–10
1280
0500
0
1600
0640
10
1920
0780
20
2240
08C0
30
2560
0A00
40
2880
0B40
50
3200
0C80
60
3520
0DC0
70
3840
0F00
80
4160
1040
90
4480
1180
100
4800
12C0
Rev. 1.1
21
Si7015-A20
5.1.4. Fast Conversion Mode
The time needed to perform a temperature or RH measurement can be reduced from 5.8 ms (typical) to 2.6 ms
(typical) by setting FAST (D5) in CONFIG (register 0x03). Fast mode reduces the total power consumed during a
conversion or the average power consumed by the Si7015 when making periodic conversions. It also reduces the
resolution of the measurements.
5.1.5. Heater
The Si7015 relative humidity sensor contains an integrated, resistive heating element that may be used to raise the
temperature of the humidity sensor. This element can be used to drive off condensation or to implement dew-point
measurement when the Si7015 is used in conjunction with a separate temperature sensor such as another Si7015.
The heater can be activated by setting HEAT (D1) in CONFIG (register 0x03). Turning on the heater will reduce the
tendency of the humidity sensor to accumulate an offset due to “memory” of sustained high humidity conditions.
When the heater is enabled, the reading of the on-chip temperature sensor will be affected (increased).
5.1.6. Device Identification
The Si7015 device and its revision level can be determined by reading ID (register 0x11). Table 15 lists the values
for the various device revisions and may include revisions not yet in existence.
Table 15. Device ID Revision Values
Device ID Value
22
D[7:4]
D[3:0]
1111
0000
Rev. 1.1
Device
Type
Revision
Level
Si7015
A
Si7015-A20
5.2. I2C Operation
The format of the address byte is shown in Table 16.
Table 16. I2C Slave Address Byte
A6
A5
A4
A3
A2
A1
A0
R/W
1
0
0
0
0
0
0
1/0
5.2.1. I2C Write Operation
To write to a register on the Si7015, the master should issue a start command (S) followed by the slave address,
0x40. The slave address is followed by a 0 to indicate that the operation is a write. Upon recognizing its slave
address, the Si7015 issues an acknowledge (A) by pulling the SDA line low for the high duration of the ninth SCL
cycle. The next byte the master places on the bus is the register address pointer, selecting the register on the
Si7015 to which the data should be transferred. After the Si7015 acknowledges this byte, the master places a data
byte on the bus. This byte will be written to the register selected by the address pointer. The Si7015 will
acknowledge the data byte, after which the master issues a Stop command (P). See Table 17.
Master Slave
Table 17. I2C Write Sequence
Sequence to Write to a Register
S
Slave Address
W
A
Address Pointer
A
Register Data
A
P
A
P
A
P
Sequence to Start a Relative Humidity Conversion
S
0x40
0
A
0x03
A
0x01
Sequence to Start a Temperature Conversion
S
0x40
0
A
0x03
Rev. 1.1
A
0x11
23
Si7015-A20
5.2.2. I2C Read Operation
To read a register on the Si7015, the master must first set the address pointer to indicate the register from which
the data is to be transferred. Therefore, the first communication with the Si7015 is a write operation. The master
should issue a start command (S) followed by the slave address, 0x40. The slave address is followed by a 0 to
indicate that the operation is a write. Upon recognizing its slave address, the Si7015 will issue an acknowledge (A)
by pulling the SDA line low for the high duration of the ninth SCL cycle. The next byte the master places on the bus
is the register address pointer selecting the register on the Si7015 from which the data should be transferred. After
the Si7015 acknowledges this byte, the master issues a repeated start command (Sr) indicating that a new transfer
is to take place. The Si7015 is addressed once again with the R/W bit set to 1, indicating a read operation. The
Si7015 will acknowledge its slave address and output data from the previously-selected register onto the data bus
under the control of the SCL signal, the master should not acknowledge (A) the data byte and issue a stop (P)
command (see Table 22). However, if a RH or Temperature conversion result (two bytes) is to be read, the master
should acknowledge (A) the first data byte and continue to activate the SCL signal. The Si7015 will automatically
output the second data byte. Upon receiving the second byte, the master should issue a not Acknowledge (A)
followed by a stop command. (See Table 23.)
Table 18. I2C Read Sequence for a Single Register
Sequence to Read from a Single Register
S
Slave Address
W
A
Address Pointer
A
Sr
Slave Address
R
A
Register Data
A
P
1
A
ID
A
P
1
A
A
P
Sequence to Read Device ID
S
0x40
0
A
0x11
A
Sr
0x40
Sequence to Read RDY bit
S
0x40
0
0x00
A
A
Sr
0x40
—
RDY
Table 19. I2C Read Sequence for RH or Temperature Conversion Result
Sequence to Read Conversion Result
S
Slave
Address
W
A
Address
Pointer
A
Sr
Slave
Address
R
A
Register 1
Data
A
Register 2
Data
A
P
S
0x40
0
A
0x01
A
Sr
0x40
1
A
Data H
A
Data L
A
P
24
Rev. 1.1
Si7015-A20
5.2.3. Firmware Revision
The internal firmware revision can be read with the following I2C transaction:
S
R
Slave
Address
A
FWREV
A
W
A
0x84
NA
A
0xB8
A
S
Slave
Address
P
The values in this field are encoded as follows:
0xFF = Firmware revision 1.0
0x20 = Firmware revision 2.0
Rev. 1.1
25
Si7015-A20
6. Control Registers
Table 20 contains a summary of the Si7015 register set. Each register is described in more detail below.
Table 20. Si7015 Register Summary
Register
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
RSVD
RSVD
RSVD
/RDY
I2C Register Summary
0x00
STATUS
RSVD
RSVD
RSVD
RSVD
0x01
DATAh
Relative Humidity or Temperature, High Byte
0x02
DATAl
Relative Humidity or Temperature, Low Byte
0x03
CONFIG
RSVD
RSVD
FAST
TEMP
RSVD
RSVD
HEAT
START
0x11
ID
ID3
ID2
ID1
ID0
0
0
0
0
0x84 0xB8
FWREV
MAJREV
MINREV
Notes:
1. Any register address not listed here is reserved and must not be written.
2. Reserved register bits (RSVD) must always be written as zero; the result of a read operation on these bits is undefined.
6.1. Register Detail
Register 0. STATUS
Bit
D7
D6
D5
D4
D3
D2
D0
Name
/RDY
Type
R
Reset Settings = 0000_0001
Bit
7:1
0
26
D1
Name
Function
Reserved Reserved. Reads undefined.
/RDY
Ready.
0 = conversion complete; results available in DATAh:DATAl.
1 = conversion in progress.
Rev. 1.1
Si7015-A20
Register 0x01. DATAh
Bit
D7
D6
D5
D4
D3
D2
Name
Relative Humidity or Temperature, High Byte
Type
R
D1
D0
Reset Settings = 0000_0000
Bit
Name
7:0
DATAh
Function
Data, High Byte.
Eight most significant bits of a temperature or humidity measurement. See Table 11 or
Table 13 for the measurement format.
Register 0x02. DATAI
Bit
D7
D6
D5
D4
D3
D2
Name
Relative Humidity or Temperature, Low Byte
Type
Read
D1
D0
Reset Settings = 0000_0000
Bit
Name
7:0
DATAl
Function
Data, Low Byte.
Eight least significant bits of a temperature or humidity measurement. See Table 11 or
Table 13 for the measurement format.
Rev. 1.1
27
Si7015-A20
Register 0x03. CONFIG
Bit
D7
D6
D5
D4
Name
FAST
Type
R/W
D3
D2
D1
D0
TEMP
HEAT
START
R/W
R/W
R/W
Reset Settings = 0000_0000
Bit
7:6
Name
Function
Reserved Reserved. Reads undefined. Always write as zero.
5
FAST
Fast Mode Enable.
0 = 5.8 ms (typical)
1 = 2.6 ms (typical)
4
TEMP
Temperature Enable.
0 = Relative humidity
1 = Temperature
3:2
Reserved Reserved. Reads undefined. Always write as zero.
1
HEAT
Heater Enable.
0 = heater off
1 = heater on
0
START
Conversion Start.
0 = do not start a conversion
1 = start a conversion
Register 0x11. ID
Bit
D7
D6
D5
D4
D3
D2
D1
D0
Name
ID7
ID6
ID5
ID4
ID3
ID2
ID1
ID0
Type
R
R
R
R
R
R
R
R
Reset Settings = 0101_0000
28
Bit
Name
7:0
ID
Function
Identification.
See Section “5.1.6. Device Identification” for reset settings.
Rev. 1.1
Si7015-A20
Register 0x84 0xB8. FWREV
Bit
D7
D6
D5
D4
D3
D2
D1
Name
MAJREV
MINREV
Type
R
R
Bit
Name
7:4
MAJREV
Major firmware revision number
3:0
MINREV
Minor firmware revision number
D0
Function
Rev. 1.1
29
Si7015-A20
DNC
DNC
DNC
DNC
DNC
GND
24
23
22
21
20
19
7. Pin Descriptions: Si7015
DNC
5
14 DNC
DNC
6
13 DNC
12
15 CS
DNC
4
11
SDA
GND
16 DNC
10
3
DNC
SCL
9
17 DNC
VDD
2
8
DNC
GND
18 DNC
7
1
DNC
GND
Table 21. Pin Descriptions
Pin #
Pin Name
Pin Type*
1, 8, 11, 19
GND
G
2, 5–7, 12–14,
16–18, 20–24
DNC
3
SCL
Description
Ground.
Do Not Connect.
Do not connect any of these pins to supply, ground or any other
signal. Internal pull-ups or pull-downs will prevent any of these pins
from floating.
I
I2C Clock Signal.
This pin is voltage-tolerant. See Table 2.
4
SDA
I/O
I2C Data Signal.
This pin is voltage-tolerant. See Table 2.
9
VDD
S
VDD Power Supply (1.9 V < VDD < 3.6 V).
10
DNC
I
If Si7015 is replacing an Si7005, the capacitor connected to Pin 10
may be left connected or removed.
15
CS
I
Chip Select—Active Low Signal.
Epad
TGND
G
Thermal Paddle.
This pad is connected to GND internally. The pad can be connected to GND externally or it can be left open-circuit and used as
a thermal input to the on-chip temperature sensor.
*Note: G = Ground, S = Power Supply, I = Digital Input, O = Digital Output, I/O = Input/Output.
30
Rev. 1.1
Si7015-A20
8. Ordering Guide
Table 22. Si7015 Device Ordering Guide
Max Accuracy
P/N
Description
Temp
RH
Pkg
Operating
Range (°C)
Protective
Cover
Packing
Format
Si7015-A20-FM
Digital temperature/
humidity sensor
±1 °C
±4.5%
QFN-24
0 to 70 °C
N
Tube
Si7015-A20-FMR
Digital temperature/
humidity sensor
±1 °C
±4.5%
QFN-24
0 to 70 °C
N
Tape-and-reel
Si7015-A20-FM1
Digital temperature/
humidity sensor
±1 °C
±4.5%
QFN-24
0 to 70 °C
Y
Cut tape
Si7015-A20-FM1R
Digital temperature/
humidity sensor
±1 °C
±4.5%
QFN-24
0 to 70 °C
Y
Tape-and-reel
Si7015-A20-GM
Digital temperature/
humidity sensor
±1 °C
±4.5%
QFN-24
–40 to
+85 °C
N
Tube
Si7015-A20-GMR
Digital temperature/
humidity sensor
±1 °C
±4.5%
QFN-24
–40 to
+85 °C
N
Tape-and-reel
Si7015-A20-GM1
Digital temperature/
humidity sensor
±1 °C
±4.5%
QFN-24
–40 to
+85 °C
Y
Cut tape
Si7015-A20-GM1R
Digital temperature/
humidity sensor
±1 °C
±4.5%
QFN-24
–40 to
+85 °C
Y
Tape-and-reel
Note: The "A" denotes product revision A and "20" denotes firmware version 2.0.
Rev. 1.1
31
Si7015-A20
9. Package Outline
9.1. 24-Pin QFN
Figure 8 illustrates the package details for the Si7015. Tables 23 and 24 list the values for the dimensions shown in
the illustration. There are two package variants with slightly different height dimensions. The two package variants
are otherwise interchangeable.
Figure 8. 24-Pin Quad Flat No Lead (QFN)
Table 23. 24-Pin Package Diagram Dimensions
Dimension
Min
Nom
Max
Dimension
Min
Nom
Max
A1
0.00
0.02
0.05
H1
1.03
1.08
1.13
b
0.18
0.25
0.30
H2
D
D2
4.00 BSC.
2.55
e
2.75
0.50 BSC.
E
E2
2.65
4.00 BSC.
2.55
2.65
2.75
1.68 REF
L
0.30
0.35
0.40
aaa
—
—
0.15
bbb
—
—
0.15
ccc
—
—
0.08
ddd
—
—
0.10
Notes:
1. Dimensioning and Tolerancing per ANSI Y14.5M-1994.
2. Recommended card reflow profile is per the JEDEC/IPC J-STD-020 specification for Small Body Components.
Table 24. Package Variants
Variant A
Variant B
Dimension
Min
Nom
Max
Min
Nom
Max
A
0.80
0.90
1.00
0.70
0.75
0.80
Note: All Dimensions are in mm unless otherwise noted.
32
Rev. 1.1
Si7015-A20
9.2. 24-Pin QFN with Protective Cover
Figure 9 illustrates the package details for the Si7015 with the optional protective cover. Tables 25 and 26 list the
values for the dimensions shown in the illustration. There are two package variants with slightly different height
dimensions. The two package variants are otherwise interchangeable.
Figure 9. 24-Pin Quad Flat No Lead (QFN) With Protective Cover
Table 25. 24-Pin Package Diagram Dimensions
Dimension
Min
Nom
Max
Dimension
Min
Nom
Max
A1
0.00
0.02
0.05
h
0.76
0.83
0.90
b
0.18
025
0.30
L
0.30
0.35
0.40
R1
0.45
0.50
0.55
2.75
aaa
—
—
0.15
D
D2
4.00 BSC.
2.55
2.65
e
0.50 BSC.
bbb
—
—
0.15
E
4.00 BSC.
ccc
—
—
0.08
ddd
—
—
0.10
E2
2.55
2.65
2.75
F1
3.60
3.75
3.90
F2
3.60
3.75
3.90
Notes:
1. Dimensioning and Tolerancing per ANSI Y14.5M-1994.
2. Recommended card reflow profile is per the JEDEC/IPC J-STD-020 specification for Small Body Components.
Table 26. Package Variants
Variant A
Variant B
Dimension
Min
Nom
Max
Min
Nom
Max
A
—
1.27
1.41
—
1.07
1.21
A2
0.80
0.90
1.00
0.70
0.75
0.80
Note: All Dimensions are in mm unless otherwise noted.
Rev. 1.1
33
Si7015-A20
10. PCB Land Pattern and Solder Mask Design
Figure 10 illustrates the recommended PCB land pattern for use with the Si7015's 4x4 mm QFN package.
Figure 10. Typical QFN-24 PCB Land Pattern
34
Rev. 1.1
Si7015-A20
Table 27. PCB Land Pattern Dimensions
Symbol
mm
C1
4.00
C2
4.00
E
0.50
P1
2.75
P2
2.75
X1
0.30
Y1
0.75
Notes:
General
1. All dimensions shown are at Maximum Material Condition (MMC). Least
Material Condition (LMC) is calculated based on a Fabrication Allowance of
0.05 mm.
2. This Land Pattern Design is based on the IPC-7351 guidelines.
Solder Mask Design
3. All metal pads are to be non-solder mask defined (NSMD). Clearance
between the solder mask and the metal pad is to be 60 µm minimum, all the
way around the pad.
Stencil Design
4. A stainless steel, laser-cut and electro-polished stencil with trapezoidal walls
should be used to assure good solder paste release.
5. The stencil thickness should be 0.125 mm (5 mils).
6. The ratio of stencil aperture to land pad size should be 1:1 for all perimeter
pins.
7. A 2x2 array of 0.95 mm square openings on 1.35 mm pitch should be used
for the center ground pad.
Card Assembly
8. A No-Clean, Type-3 solder paste is recommended.
9. The recommended card reflow profile is per the JEDEC/IPC J-STD-020
specification for Small Body Components.
Rev. 1.1
35
Si7015-A20
11. Top Marking
11.1. Si7015 Top Marking
11.2. Top Marking Explanation
Mark Method:
Laser
Pin 1 Indicator:
Circle = 0.3 mm Diameter
Upper-Left Corner
Font Size:
0.40 mm
Line 1 Marking:
TTTT = Manufacturing Code
Note: The top mark may not be visible if the optional protective cover is installed. If
needed, the device can be identified by reading the identification register as
explained in Section “5.1.6. Device Identification”.
36
Rev. 1.1
Si7015-A20
12. Additional Reference Resources
AN607:
Si70xx Humidity Sensor Designer’s Guide
AN764: Upgrading from the Si7005 to the Si7015
Rev. 1.1
37
Si7015-A20
DOCUMENT CHANGE LIST
Revision 0.9 to Revision 1.0

Updated document revision to 1.0.
Revision 1.0 to Revision 1.1
 Minor modification to description and dimensions of
protective cover due to the addition of a second cover
supplier.
38
Rev. 1.1
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