Rev. 1.3 8/16 Copyright © 2016 by Silicon La boratories Si7013-A20
Si7013-A20
I2C HUMIDITY AND TWO-ZONE TEMPERATURE SENSOR
Features
Applications
Description
The Si7013 I2C Humidity and 2-Zone Temperature Sensor is a monolithic CMOS
IC integrating humidity and temperature sensor elements, an analog-to-digital
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.
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.
An auxiliary sensor input with power management can be tied directly to an
external thermistor network or other voltage-output sensor. On-board logic
performs calibration/linearization of the external input using user-programmable
coefficients. The least-significant bit of the Si7013's I2C address is programmable,
allowing two devices to share the same bus.
The Si7013 is available in a 3x3 mm DFN package and is reflow solderable. 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 Si7013 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.
Precision Relative Humidity Sensor
 ± 3% RH (max), 0–80% RH
High Accuracy Temperature Sensor
±0.4 °C (max), –10 to 85 °C
0 to 100% RH operating range
Up to –40 to +125 °C operating
range
Low Voltage Operation (1.9 to 3.6 V)
Low Power Consumption
150 µA active current
60 nA standby current
Factory-calibrated
I2C Interface
Integrated on-chip heater
Auxiliary Sensor input
Direct readout of remote
thermistor temperature in °C
Package: 3x3 mm DFN
Excellent long term stability
Optional factory-installed cover
Low-profile
Protection during reflow
Excludes liquids and particulates
HVAC/R
Thermostats/humidistats
Instrumentation
White goods
Micro-environments/data centers
Industrial Controls
Indoor weather stations
Patent Protected. Patents pending
Ordering Information:
See page 38.
Pin Assignments
SDA
GNDD
VSNS
AD0/VOUT
GNDA
VINP
VDDD
SCL
VINN
VDDA
1
2
3
4
56
7
8
9
10
Top View
Si7013-A20
2 Rev. 1.3
Functional Block Diagram
ADC
GND
Humidity
Sensor
Control Logic
SCL
Si7013
Temp
Sensor
1.25V
Ref
I2C Interface SDA
AD0/VOUT
VSNS Vdd
VINP
Calibration
Memory
Analog
Input
VINN
Si7013-A20
Rev. 1.3 3
TABLE OF CONTENTS
Section Page
1. Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
2. Typical Application Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
3. Bill of Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
4. Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
4.1. Relative Humidity Sensor Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
4.2. Hysteresis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
4.3. Prolonged Exposure to High Humidity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
4.4. PCB Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
4.5. Protecting the Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
4.6. Bake/Hydrate Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
4.7. Long Term Drift/Aging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
5. I2C Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
5.1. Issuing a Measurement Command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
5.2. Reading and Writing User Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
5.3. Measuring Analog Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
5.4. Nonlinear Correction of Voltage Inputs: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
5.5. Firmware Revision . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
5.6. Heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
5.7. Electronic Serial Number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
6. Control Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
6.1. Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
7. Pin Descriptions: Si7013 (Top View) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37
8. Ordering Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38
9. Package Outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39
9.1. Package Outline: 3x3 10-pin DFN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39
9.2. Package Outline: 3x3 10-pin DFN with Protective Cover . . . . . . . . . . . . . . . . . . . . . 40
10. PCB Land Pattern and Solder Mask Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41
11. Top Marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42
11.1. Si7013 Top Marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42
11.2. Top Marking Explanation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42
12. Additional Reference Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43
Document Change List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44
Si7013-A20
4 Rev. 1.3
1. Electrical Specifications
Unless otherwise specified, all min/max specifications apply over the recommended operating conditions.
Table 1. Recommended Operating Conditions
Parameter Symbol Test Condition Min Typ Max Unit
Power Supply VDD 1.9 3.6 V
Operating Temperature TAI and Y grade –40 +125 °C
Operating Temperature TAG grade –40 +85 °C
Table 2. General Specifications
1.9 < VDD <3.6 V; TA= –40 to 85 °C (G grade) or –40 to 125 °C (I/Y grade); default conversion time unless otherwise noted.
Parameter Symbol Test Condition Min Typ Max Unit
Input Voltage High VIH AD0, SCL, SDA, VSNS pins 0.7xVDD ——V
Input Voltage Low VIL AD0, SCL, SDA, VSNS pins 0.3xVDD V
Input Voltage Range VIN SCL, SDA, VSNS pins with respect to
GND
0.0 VDD V
Input Leakage IIL SCL, SDA pins; VIN =GND 1 μA
VSNS pin (200K nominal pull up);
Vin = GND
5xVDD μA
Output Voltage Low VOL SDA pin; IOL =2.5mA; VDD = 3.3 V 0.6 V
SDA pin; IOL =1.2mA;
VDD =1.9V
——0.4V
Output Voltage High VOH VOUT pin, IOH = –0.5 mA, VDD =2.0V V
DD – 0.2 V
VOUT pin, IOH = –10 μAV
DD– 0.1 V
VOUT pin, IOH = –1.7 mA, VDD =3.0V V
DD – 0.4 V
Current
Consumption
IDD RH conversion in progress 150 180 μA
Temperature conversion in progress 90 120 μA
Standby, –40 to +85 °C2—0.060.62μA
Standby, –40 to +125 °C2—0.063.8μA
Peak IDD during powerup3—3.54.0mA
Peak IDD during I2C operations4—3.54.0mA
Heater Current5 IHEAT 3.1 to 94.2 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 Reset, Read/Write User Registers, Read EID, Read Firmware Version, Read/Write
Thermistor Coefficients and Measure Analog Voltage or Thermistor Temperature. Duration is <50 μs for all commands
except Measure Analog Voltage or Thermistor Temperature, which has <150 μs duration when Thermistor Correction is
enabled.
5. Additional current consumption when HTRE bit enabled. See Section “5.6. Heater” for more information.
Si7013-A20
Rev. 1.3 5
Conversion Time1tCONV 12-bit RH 10 12
ms
11-bit RH 5.8 7
10-bit RH 3.7 4.5
8-bit RH 2.6 3.1
14-bit temperature 7 10.8
13-bit temperature 4 6.2
12-bit temperature 2.4 3.8
11-bit temperature 1.5 2.4
Voltage Normal 7
Voltage Fast 3.1
Powerup Time tPU From VDD 1.9 V to ready for a
conversion, 25 °C
—1825ms
From VDD 1.9 V to ready for a
conversion, full temperature range
——80ms
After issuing a software reset
command
—515ms
Table 3. I2C Interface Specifications1
1.9 VDD 3.6 V; TA = –40 to +85 °C (G grade) or –40 to +125 °C (I/Y grade) unless otherwise noted.
Parameter Symbol Test Condition Min Typ Max Unit
Hysteresis VHYS High-to-low versus
low-to-high transition
0.05 x VDD ——V
SCLK Frequency2fSCL 400 kHz
SCL High Time tSKH 0.6 µs
Notes:
1. All values are referenced to VIL and/or VIH.
2. Depending on the conversion command, the Si7013 may hold the master during the conversion (clock stretch). At
above 300 kHz SCL, the Si7013 may hold the master briefly for user register and device ID transactions. At the highest
I2C speed of 400 kHz the stretching will be <50 µs.
3. Pulses up to and including 50 ns will be suppressed.
Table 2. General Specifications (Continued)
1.9 < VDD <3.6 V; TA= –40 to 85 °C (G grade) or –40 to 125 °C (I/Y grade); default conversion time unless otherwise noted.
Parameter Symbol Test Condition Min Typ Max Unit
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 Reset, Read/Write User Registers, Read EID, Read Firmware Version, Read/Write
Thermistor Coefficients and Measure Analog Voltage or Thermistor Temperature. Duration is <50 μs for all commands
except Measure Analog Voltage or Thermistor Temperature, which has <150 μs duration when Thermistor Correction is
enabled.
5. Additional current consumption when HTRE bit enabled. See Section “5.6. Heater” for more information.
Si7013-A20
6 Rev. 1.3
Figure 1. I2C Interface Timing Dia gram
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 Between Stop and Start 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
Suppressed Pulse Width3tSP 50 ns
Table 3. I2C Interface Specifications1 (Continued)
1.9 VDD 3.6 V; TA = –40 to +85 °C (G grade) or –40 to +125 °C (I/Y grade) unless otherwise noted.
Parameter Symbol Test Condition Min Typ Max Unit
Notes:
1. All values are referenced to VIL and/or VIH.
2. Depending on the conversion command, the Si7013 may hold the master during the conversion (clock stretch). At
above 300 kHz SCL, the Si7013 may hold the master briefly for user register and device ID transactions. At the highest
I2C speed of 400 kHz the stretching will be <50 µs.
3. Pulses up to and including 50 ns will be suppressed.
SCL
D6
1/fSCL tSKH
SDA
tSKL
tSTH
D5 D4 D0 R/W ACK
tDS tDH
Start Bit Stop Bit
tBUF
tSTS tVD :
ACK
tSPS
tSP
Si7013-A20
Rev. 1.3 7
Table 4. Humidity Sensor
1.9 VDD 3.6 V; TA = 30 °C; default conversion time unless otherwise noted.
Parameter Symbol Test Condition Min Typ Max Unit
Operating Range1Non-condensing 0 100 %RH
Accuracy2, 3 0 – 80% RH ±2 ±3 %RH
80 – 100% RH See Figure 2. %RH
Repeatability-Noise 12-bit resolution 0.025 %RH RMS
11-bit resolution 0.05 %RH RMS
10-bit resolution 0.1 %RH RMS
8-bit resolution 0.2 %RH RMS
Response Time4τ63%
1 m/s airflow, with cover 18 S
1 m/s airflow, without cover 17
Drift vs. Temperature 0.05 %RH/°C
Hysteresis ±1 %RH
Long Term Stability3—<0.25 %RH/yr
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 “4.1. Relative Humidity Sensor Accuracy” for more details.
3. Drift due to aging effects at typical room conditions of 30°C and 30% to 50% RH. May be impacted by dust, vaporized
solvents or other contaminants, e.g., out-gassing tapes, adhesives, packaging materials, etc. See Section “4.7. 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.
Si7013-A20
8 Rev. 1.3
Figure 2. RH Accuracy at 30 °C
Si7013-A20
Rev. 1.3 9
Figure 3. Temperature Accuracy*
*Note: Applies only to I and Y devices beyond +85 °C.
Table 5. Temperature Sensor
1.9 VDD 3.6 V; TA= –40 to +85 °C (G grade) or –40 to +125 °C (I/Y grade), default conversion time unless otherwise noted.
Parameter Symbol Test Condition Min Typ Max Unit
Operating Range I and Y Grade –40 +125 °C
G Grade –40 +85 °C
Accuracy1–10 °C < tA<85 °C ±0.3 ±0.4 °C
–40 °C < tA<125 °C Figure 3. °C
Repeatability-Noise 14-bit resolution 0.01 °C RMS
13-bit resolution 0.02 °C RMS
12-bit resolution 0.04 °C RMS
11-bit resolution 0.08 °C RMS
Response Time2τ63% Unmounted device 0.7 s
Si7013-EB board 5.1 s
Long Term Stability < 0.01 °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 airflow.
Si7013-A20
10 Rev. 1.3
Table 6. Voltage Converter Specifications
1.9 VDD 3.6 V; TA= –40 to +85 °C (G grade) or –40 to +125 °C (I/Y grade); normal mode conversion time, VREF =1.25V
internal or VDDA, buffered and unbuffered mode, unless otherwise noted.
Parameter Symbol Test Condition Min Typ Max Unit
Resolution VREF/
32768
—V
Integral Non-linearity INL |VINP-VINN| < VREF/2 1 LSB
Differential Non-linearity DNL |VINP-VINN| < VREF/2 1 LSB
Noise N |VINP-VINN| < VREF/2,
VREF = 1.25 V, Normal Mode
—25—µV
RMS
|VINP-VINN| < VREF/2,
VREF = 1.25 V, Fast Mode
—50—
Input Offset
(Buffered Mode)
VOS |VINP-VINN| = 0 10 mV
Input Offset
(Unbuffered Mode)1,2
VOS |VINP-VINN| = 0 1 mV
Gain Accuracy GV
REF = 1.25 V; gain is absolute +1+2%
VREF =V
DD; gain is relative to VDD —+0.25 +0.5 %
Notes:
1. Guaranteed by design.
2. In unbuffered mode, RIN*CIN should be < 0.5usec. CIN minimum is around 10 pF.
Si7013-A20
Rev. 1.3 11
Table 7. Thermal Characteristics
Parameter Symbol Test Condition DFN-6 Unit
Junction to Air Thermal Resistance JA JEDEC 2-Layer board,
No Airflow
236 °C/W
Junction to Air Thermal Resistance JA JEDEC 2-Layer board,
1 m/s Airflow
203 °C/W
Junction to Air Thermal Resistance JA JEDEC 2-Layer board,
2.5 m/s Airflow
191 °C/W
Junction to Case Thermal Resistance JC JEDEC 2-Layer board 20 °C/W
Junction to Board Thermal Resistance JB JEDEC 2-Layer board 112 °C/W
Table 8. Absolute Maximum Ratings1,2
Parameter Symbol Test Condition Min Typ Max Unit
Ambient temperature
under bias
–55 125 °C
Storage Temperature –65 150 °C
Voltage on I/O pins –0.3 VDD+0.3 V V
Voltage on VDD with
respect to GND
–0.3 4.2 V
ESD Tolerance HBM 2 kV
CDM 1.25 kV
MM 250 V
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 application note, “AN607: Si70xx Humidity Sensor Designer’s Guide” for
details.
Si7013-A20
12 Rev. 1.3
2. Typical Application Circuits
The primary function of the Si7013 is to measure relative humidity and temperature. Figure 4 demonstrates the
typical application circuit to achieve these functions; pins 6 and 7 are not required and should be left unconnected.
Figure 4. Typical Application Circuit for Relative Humidity and Temperature Measurement
The application circuit shown in Figure 5 uses the auxiliary analog pins for measuring a remote temperature using
a thermistor.
Figure 5. Typical Application Circuit for Thermistor Interface with AD0 = 1
The voltage connected at VDDA serves as the reference voltage for both the Analog-to-Digital converter and the
resistor string. Therefore, the ADC must be configured to take its reference from VDDA. The top of the resistor
string is connected to the VOUT pin, allowing the resistor string to be powered down, saving power between
temperature conversions. In this mode of operation, the analog inputs are buffered and present an input
impedance of > 100 k
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0.1µF
GNDD
VDDD
SCL
SDA
Si7013
SCL
SDA
1.9V to 3.6V
AD0/VOUT
VINP
VINN
C2
0.1µF
R3
24k
R4
24k
TH1
10k
NTC
VDDA
GNDA
10
1
98
2
6
7
34
5
VSNS
R1
10k
R2
10k
C3
0.1µF
Si7013-A20
Rev. 1.3 13
The AD0/VOUT pin is a dual function pin. At powerup, it functions as an address select pin and selects the least
significant I2C Figure 5, the AD0/VOUT pin is pulled high, selecting AD0 = 1. In Figure 6, the AD0/VOUT pin is
pulled low selecting AD0 = 0.
Figure 6. Typical Application Circuit for Thermistor Interface with AD0 = 0
Figure 7. Typical Application Circuit for Single Ended 0 to 3 V Measurement
Figure 7 demonstrates a single ended 0 to 3 V input range configuration. The voltage reference is the internal
1.25 V reference. The 1 k and 2 k resistor divider keeps the voltage range to 1.0 V, which is within the
recommended 80% of VREF
. Full scale of 32767 counts is 3.75 V.
C1
0.1µF
GNDD
VDDD
SCL
SDA
Si7013
SCL
SDA
1.9 to 3.6V
AD0/VOUT
VINP
VINN
C2
0.1µF R3
24k
R4
24k
VDDA
GNDA
10
1
98
2
6
7
34
5
VSNS
R1
10k
R2
10k
TH1
10k
NTC
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Si7013-A20
14 Rev. 1.3
3. Bill of Materials
Table 9. Typical Application Circuit BOM for Relative Humidity and Temperature Measurement
Reference Description Mfr Part Number Manufacturer
R1 Resistor, 10 k, ±5%, 1/16W, 0603 CR0603-16W-103JT Venkel
R2 Resistor, 10 k, ±5%, 1/16W, 0603 CR0603-16W-103JT Venkel
C1 Capacitor, 0.1 µF, 16 V, X7R, 0603 C0603X7R160-104M Venkel
U1 IC, Digital Temperature/humidity Sensor Si7013-A20 Silicon Labs
Table 10. Typical Application Circuit BOM for Thermistor Interface
Reference Description Mfr Part Number Manufacturer
R1 Resistor, 10 k, ±5%, 1/16W, 0603 CR0603-16W-103JT Venkel
R2 Resistor, 10 k, ±5%, 1/16W, 0603 CR0603-16W-103JT Venkel
R3 Resistor, 24 k, ±1%, 1/16W, 0603 CR0603-16W-2402F Venkel
R4 Resistor, 24 k, ±1%, 1/16W, 0603 CR0603-16W-2402F Venkel
C1 Capacitor, 0.1 µF, 16 V, X7R, 0603 C0603X7R160-104M Venkel
C2 Capacitor, 0.1 µF, 16 V, X7R, 0603 C0603X7R160-104M Venkel
TH1 Thermistor, 10 kNTCLE100E3103 Vishay
U1 IC, digital temperature/humidity sensor Si7013-A20 Silicon Labs
Table 11. Typical Application Circuit BOM for Single Ended 0 to 3 V Measurement
Reference Description Mfr Part Number Manufacturer
R1 Resistor, 10 k, ±5%, 1/16W, 0603 CR0603-16W-103JT Venkel
R2 Resistor, 10 k, ±5%, 1/16W, 0603 CR0603-16W-103JT Venkel
R3 Resistor, 2 k, ±1%, 1/16W, 0603 CR0603-16W-2001F Venkel
R4 Resistor, 1 k, ±1%, 1/16W, 0603 CR0603-16W-1001F Venkel
C1 Capacitor, 0.1 µF, 16 V, X7R, 0603 C0603X7R160-104M Venkel
U1 IC, Digital Temperature/humidity Sensor Si7013-A20 Silicon Labs
Si7013-A20
Rev. 1.3 15
4. Functional Description
Figure 8. Si7013 Block Diagram
The Si7013 is a digital relative humidity and temperature sensor that integrates temperature and humidity sensor
elements, an analog-to-digital converter, signal processing, calibration, polynomial non-linearity correction, and an
I2C interface all in a single chip. The Si7013 is individually factory-calibrated for both temperature and humidity,
with the calibration data stored in on-chip non-volatile memory. This ensures that the sensor is fully
interchangeable, with no recalibration or changes to software required. Patented use of industry-standard CMOS
and low-K dielectrics as a sensor enables the Si7013 to achieve excellent long term stability and immunity to
contaminants with low drift and hysteresis. The Si7013 offers a low power, high accuracy, calibrated and stable
solution ideal for a wide range of temperature, humidity, and dew-point applications including medical and
instrumentation, high reliability automotive and industrial systems, and cost-sensitive consumer electronics.
The auxiliary sensor input option exists to use the ADC with external inputs and reference. Suitable buffers are
included to allow the part to be connected to high impedance circuitry such as bridges or other types of sensors,
without introducing errors.
While the Si7013 is largely a conventional mixed-signal CMOS integrated circuit, relative humidity sensors in
general and those based on capacitive sensing using polymeric dielectrics 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 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.
Si7013-A20
16 Rev. 1.3
4.1. 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 25–30 °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 trace in Figure 9 shows the result
of a typical sweep.
Figure 9. Measuring Sensor Accuracy Including Hysteresis
The RH accuracy is defined as the dotted line shown in Figure 9, 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 Si7013 accuracy
specification (Table 4) includes:
Unit-to-unit and lot-to-lot variation
Accuracy of factory calibration
Margin for shifts that can occur during solder reflow
The accuracy specification does not include:
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
Si7013-A20
Rev. 1.3 17
4.2. 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 trace
in Figure 9. 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 error (dashed trace). In the example of
Figure 9, the measurement uncertainty due to the hysteresis effect is +/-1.0%RH.
4.3. 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 “4.6. Bake/Hydrate Procedure” ).
4.4. PCB Assembly
4.4.1. Soldering
Like most ICs, Si7013 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:
Si7013 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.
Si7013s 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.
4.4.2. 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 Si7013 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.
Si7013-A20
18 Rev. 1.3
4.4.3. 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 “AN607: Si70xx Humidity Sensor
Designer’s Guide” for more information on cleaning.
Minimize the heating of the device. Soldering iron temperatures 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 10. Si70xx with Factory-Installed Protective Cover
Si7013-A20
Rev. 1.3 19
4.5. 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 Si7013 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 12.
Table 12. Specifications of Protective Cover
Parameter Value
Material PTFE
Operating Temperature –40 to 125 °C
Maximum Reflow Temperature 260 °C
IP Rating (per IEC 529) IP67
Si7013-A20
20 Rev. 1.3
4.6. 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:
Baking the sensor at 125 °C for 12 hours
Hydration 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.
4.7. 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 Si7013 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 effects of damage, contamination, or exposure to extreme
environmental conditions.
Si7013-A20
Rev. 1.3 21
5. I2C Interface
The Si7013 communicates with the host controller over a digital I2C interface. The 7-bit base slave address is 0x40
or 0x41; the least significant bit is pin programmable.
Master I2C devices communicate with the Si7013 using a command structure. The commands are listed in the I2C
command table. Commands other than those documented below are undefined and should not be sent to the
device.
Table 13. I2C Slave Address Byte
A6 A5 A4 A3 A2 A1 A0 R/W
100000AD01/0
Table 14. I2C Command Table
Command Description Command Code
Measure Relative Humidity, Hold Master Mode 0xE5
Measure Relative Humidity, No Hold Master Mode 0xF5
Measure Temperature, Hold Master Mode 0xE3
Measure Temperature, No Hold Master Mode 0xF3
Measure Analog Voltage or Thermistor Temperature 0xEE
Read Temperature Value from Previous RH Measurement 0xE0
Reset 0xFE
Write Voltage Measurement Setup (User register 2) 0x50
Read Voltage Measurement Setup (User register 2) 0x10
Write RH/T Measurement Setup (User register 1) 0xE6
Read RH/T Measurement Setup (User register 1) 0xE7
Write Heater Setup (User register 3) 0x51
Read Heater Setup (User register 3) 0x11
Write Thermistor Correction Coefficient 0xC5
Read Thermistor Correction Coefficient 0x84
Read Electronic ID 1st Word 0xFA 0x0F
Read Electronic ID 2nd Word 0xFC 0xC9
Read Firmware Revision 0x84 0xB8
Si7013-A20
22 Rev. 1.3
5.1. Issuing a Measurement Command
The measurement commands instruct the Si7013 to perform one of four possible measurements; Relative
Humidity, Temperature, Auxiliary Temperature, or Analog Voltage. While the measurement is in progress, the
option of either clock stretching (Hold Master Mode) or Not Acknowledging read requests (No Hold Master Mode)
is available to indicate to the master that the measurement is in progress. For Humidity and Temperature
measurements, the chosen command code determines which mode is used. For Auxiliary Temperature and Analog
Voltage measurements, No Hold Master mode can be enabled by writing a "1" to bit D6 in register 2. Note that
internal Humidity and Temperature measurements should not be made with this bit set.
Optionally, a checksum byte can be returned from the slave for use in checking for transmission errors for Relative
Humidity and Temperature measurements. The checksum byte is optional after initiating an RH or temperature
measurement with commands 0xE5, 0xF5, 0xE3 and 0xF3. The checksum byte is required for reading the
electronic ID with commands 0xFA 0x0F and 0xFC 0xC9. For all other commands, the checksum byte is not
supported. The checksum byte will follow the least significant measurement byte if it is acknowledged by the
master. The checksum byte is not returned if the master “not acknowledges” the least significant measurement
byte. The checksum byte is calculated using a CRC generator polynomial of x8 + x5 + x4 + 1 with an initialization of
0x00.
In the I2C sequence diagrams in the following sections, bits produced by the master and slave are color coded as
shown:
Table 15. I2C Bit Descriptions
Name Symbol Description
START S SDA goes low while SCL high.
STOP P SDA goes high while SCL high.
Repeated START Sr SDA goes low while SCL high. It is allowable to generate a STOP before the
repeated start. SDA can transition to high before or after SCL goes high in
preparation for generating the START.
READ R Read bit = 1
WRITE W Write bit = 0
All other bits SDA value must remain high or low during the entire time SCL is high (this is
the set up and hold time in Figure 1).
Master Slave
Si7013-A20
Rev. 1.3 23
*Note: Device will NACK the slave address byte until conversion is complete.
Si7013-A20
24 Rev. 1.3
5.1.1. Measuring Relative Humidity
Once a relative humidity measurement has been made, the results of the measurement may be converted to
percent relative humidity by using the following expression:
Where:
%RH is the measured relative humidity value in %RH
RH Code is the 16-bit word returned by the Si7013
A humidity measurement will always return XXXXXX10 in the LSB field.
Note: 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 out-
side of this range.
5.1.2. Measuring Temperature
Each time a relative humidity measurement is made a temperature measurement is also made for the purposes of
temperature compensation of the relative humidity measurement. If the temperature value is required, it can be
read using command 0xE0; this avoids having to perform a second temperature measurement. The measure
temperature commands 0xE3 and 0xF3 will perform a temperature measurement and return the measurement
value, command 0xE0 does not perform a measurement but returns the temperature value measured during the
relative humidity measurement. The checksum output is not available with the 0xE0 command.
The results of the temperature measurement may be converted to temperature in degrees Celsius (°C) using the
following expression:
Where:
Temperature (°C) is the measured temperature value in °C
Temp_Code is the 16-bit word returned by the Si7013
A temperature measurement will always return XXXXXX00 in the LSB field.
%RH 125RH_Code
65536
--------------------------------------- 6=
Temperature (C175.72Temp_Code
65536
--------------------------------------------------------46.85=
Si7013-A20
Rev. 1.3 25
5.2. Reading and Writing User Registers
There are three user registers on the Si7013 that allow the user to set the configuration of the Si7013, the
procedure for accessing these registers is set out below. The checksum byte is not supported after reading a user
register.
5.3. Measuring Analog Voltage
The analog voltage input pins can accept voltage inputs within the ranges shown in Table 16. VREFP is internally
connected to VDDA or to an internal 1.25 V reference voltage.
The voltage conversion output is a signed 16-bit integer that will vary from –32768 to 32767 as the input (VINP
VINN) goes from –V to +V. For best performance, it is recommended that |VINP–VINN| be limited to Vref/2. With
minor degradation in performance, this can be extended to 0.8*Vref. The checksum option for voltage mode
conversions is not supported.
Sequencetoreadaregister
SSlave
Address WAReadReg
Cmd ASr
Slave
Addres
s
R A Read
Data
NA P
Sequencetowritearegister
SSlave
Address WAWriteReg
Cmd AWriteData AP
Table 16. Analog Input Ranges
VINP Input Range VINN Input Range
Min Max Min Max
Buffered Input 0.35 V VDD–0.35 V 0.35 V VDD–0.35 V
Unbuffered Input 0 V VDD 0V V
DD
Si7013-A20
26 Rev. 1.3
5.4. Nonlinear Correction of Voltage Inputs:
The Si7013 contains a look-up table for applying non-linear correction to external voltage measurements. The look-
up table is contained in an internal, user-programmable OTP memory. The OTP memory is non-volatile, meaning
the values are retained even when the device is powered off.
Once the lookup table values have been programmed, this correction is invoked by writing a “1” to bit 5 of user
register 2. Note that humidity measurements should not be performed when this bit is set and the Si7013 must also
be power cycled after writing the coefficients before they can take effect.
5.4.1. Calculating Lookup Table Values
The non-linear correction is based on 10 points. Each point consists of the ideal output for a given expected A/D
measurement result.
Values between the ideal output points are interpolated based on the slope between the two output points.
The lookup table is stored in the Si7013 memory. Values must be programmed for each pair of input values and
ideal output points. In addition, the slope between each ideal output point must also be programmed (the Si7013
will not automatically calculate the slope). Only 9 of the input/output pairs need to be in the table because the 10th
output value is determined by the slope equation.
The table contains 3 sets of 9 values:
In(1-9): 16-bit signed values for each input point read from the ADC. See Section “5.3. Measuring Analog
Voltage” for more information on setting up the ADC measurement.
Out(1-9): 16-bit unsigned values for each ideal output point that should be used for each input point.
Slope(1-9): 16-bit signed values for the slope between each ideal output point.
Note: The table must be arranged in order of decreasing input values.
The slope values must be calculated as follows:
slopeN =256*(outputN+1 – outputN)/(inputN+1 – inputN)
The actual output value is determined by extrapolation:
If in >in2, out = out1+slope1*(in-in1)/256
Else if in >in3, out = out2+slope2*(in-in2)/256
Else if in >in4, out = out3+slope3*(in-in3)/256
Else if in >in5, out = out4+slope4*(in-in4)/256
Else if in >in6, out = out5+slope5*(in-in5)/256
Else if in >in7, out = out6+slope6*(in-in6)/256
Else if in >in8, out = out7+slope7*(in-in7)/256
Else if in >in9, out = out8+slope8*(in-in8)/256
Else out = out9+slope9*(in-in9)
Si7013-A20
Rev. 1.3 27
5.4.2. Entering Lookup Table Values into OTP Memory:
The table is entered into memory addresses 0x82 – 0xB7 one byte at a time. Until the OTP has been programmed,
all memory addresses default to a value of 0xFF. The table below indicates where the values are written:
Table 17. Lookup Table Memory Map
Name Memory
Location Name Memory
Location Name Memory
Location
Input1 (MSB) 0x82 Output1 (MSB) 0x94 Slope1 (MSB) 0xA6
Input1 (LSB) 0x83 Output1 (LSB) 0x95 Slope1 (LSB) 0xA7
Input2 (MSB) 0x84 Output2 (MSB) 0x96 Slope2 (MSB) 0xA8
Input2 (LSB) 0x85 Output2 (LSB) 0x97 Slope2 (LSB) 0xA9
Input3 (MSB) 0x86 Output3 (MSB) 0x98 Slope3 (MSB) 0xAA
Input3 (LSB) 0x87 Output3 (LSB) 0x99 Slope3 (LSB) 0xAB
Input4 (MSB) 0x88 Output4 (MSB) 0x9A Slope4 (MSB) 0xAC
Input4 (LSB) 0x89 Output4 (LSB) 0x9B Slope4 (LSB) 0xAD
Input5 (MSB) 0x8A Output5 (MSB) 0x9C Slope5 (MSB) 0xAE
Input5 (LSB) 0x8B Output5 (LSB) 0x9D Slope5 (LSB) 0xAF
Input6 (MSB) 0x8C Output6 (MSB) 0x9E Slope6 (MSB) 0xB0
Input6 (LSB) 0x8D Output6 (LSB) 0x9F Slope6 (LSB) 0xB1
Input7 (MSB) 0x8E Output7 (MSB) 0xA0 Slope7 (MSB) 0xB2
Input7 (LSB) 0x8F Output7 (LSB) 0xA1 Slope7 (LSB) 0xB3
Input8 (MSB) 0x90 Output8 (MSB) 0xA2 Slope8 (MSB) 0xB4
Input8 (LSB) 0x91 Output8 (LSB) 0xA3 Slope8 (LSB) 0xB5
Input9 (MSB) 0x92 Output9 (MSB) 0xA4 Slope9 (MSB) 0xB6
Input9 (LSB) 0x93 Output9 (LSB) 0xA5 Slope9 (LSB) 0xB7
Si7013-A20
28 Rev. 1.3
The sequences for reading and writing thermistor coefficients are given below:
For example, to program a Si7013 at slave address 0x40 with the 16-bit value 0x4C2F, starting at memory location
0x82, you would write:
<Start Condition> 0x40 W ACK 0xC5 ACK 0x82 ACK 0x4C ACK <Stop Condition>
<Start Condition> 0x40 W ACK 0xC5 ACK 0x83 ACK 0x2F ACK <Stop Condition>
The internal memory is one-time-programmable, so it is not possible to change the values once written. However,
to verify the values were written properly use command 0x84. For example, to verify that 0x4C was written to
location 0x82 use:
<Start Condition> 0x40 W ACK 0x84 ACK 0x82 ACK <Start Condition> 0x40 R ACK 0x4C NACK <Stop
Condition> where 0x4C is the expected return value of the read transaction.
Remember to power cycle the Si7013 after writing the coefficient data.
Si7013-A20
Rev. 1.3 29
5.4.3. Example Thermistor Calculations
For the Si7013 evaluation board with a 10 K ohm thermistor and two 24.3 Kbias resistors and assuming the A/D
conversion is done using VDD as a reference with buffered inputs, the ideal input voltage versus temperature is:
Vin = VDD *Rthemistor/(Rthermisor+48.6 K)
Since VDD is also the reference then the expected A/D conversion result is:
A/D counts = 32768* Rthemistor/(Rthermisor+48.6 K)
If it is desired to linearize this result for the same temperature representation as the on board temperature sensor:
Temperature °C = (Output_Code*175.72/65536 – 46.85), then the desired output code is:
Output_Code = 65536*(Temperature+46.85)/175.72
Using thermistor data sheet values of resistance versus temperature and choosing to linearize at the points –15C,
–5C, 5C, 15C, 25C, 35C, 45C, 55C, 65C and 75C results in the following. The values in gray are the table entries
for Si7013:
Table 18. Example Non-Linear Correction to Thermistor Voltage Measurements
Temperature
(Degrees C) Thermistor
Resistance Vin/VDD A/D
Codes Desired
Code Slope Table Entry
–15 71746 0.596164 19535 11879 –218 1
–5 41813 0.462467 15154 15608 –241 2
5 25194 0.34141 11187 19338 –298 3
15 15651 0.243592 7982 23067 –400 4
25 10000 0.170648 5592 26797 –563 5
35 6556 0.118863 3895 30527 –813 6
45 4401 0.83036 2721 34256 –1186 7
55 3019 0.058486 1916 37986 –1739 8
65 2115 0.041704 1367 41715 –2513 9
75 1509 0.030114 75 45445
Si7013-A20
30 Rev. 1.3
Once the table entry values are calculated, they should be programmed to the Si7013 memory locations as shown
below:
Table 19. Example Non-Linear Thermistor Correction Entries into Si7013 Memory
Memory
Location A/D
Codes Value Memory
Location Desired
Codes Value Memory
Location Slope Value
82 19535 4C 94 11879 2E A6 –218 FF
83 4F 95 67 A7 26
84 15154 3B 96 15608 3C A8 –241 FF
85 32 97 F8 A9 0F
86 11187 2B 98 19338 4B AA –298 FE
87 B3 99 8A AB D6
88 7982 1F 9A 23067 5A AC –400 FE
89 2E 9B 1B AD 70
8A 5592 15 9C 26797 68 AE –563 FD
8B D8 9D Ad AF CD
8C 3895 F 9E 30527 77 B0 –813 FC
8D 37 9F 3F B1 D3
8E 2721 A A0 34256 85 B2 –1186 FB
8F A1 A1 D0 B3 5E
90 1916 7 A2 37986 94 B4 –1739 F9
91 7C A3 62 B5 35
92 1367 5 A4 41715 A2 B6 –2513 F6
93 57 A5 F3 B7 2F
Si7013-A20
Rev. 1.3 31
5.5. Firmware Revision
The internal firmware revision can be read with the following I2C transaction:
The values in this field are encoded as follows:
0xFF = Firmware revision 1.0
0x20 = Firmware revision 2.0
5.6. Heater
The Si7013 contains an integrated resistive heating element that may be used to raise the temperature of the
sensor. This element can be used to test the sensor, to drive off condensation, or to implement dew-point
measurement when the Si7013 is used in conjunction with a separate temperature sensor such as another Si7013
(the heater will raise the temperature of the internal temperature sensor).
The heater can be activated using HTRE, bit 2 in User Register 1. Turning on the heater will reduce the tendency
of the humidity sensor to accumulate an offset due to "memory" of sustained high humidity conditions. Several
different power levels are available. The various settings are adjusted using User Register 3 and are described in
Table 20.
SSlave
Address WA0x84 A0xB8A S Slave
Address
RAFWREV NA P
Table 20. Heater Control Settings
HEATER[3:0] Typical Current
Draw* (mA)
0000 3.09
0001 9.18
0010 15.24
... ...
0100 27.39
... ...
1000 51.69
... ...
1111 94.20
*Note: Assumes VDD =3.3V.
Si7013-A20
32 Rev. 1.3
5.7. Electronic Serial Number
The Si7013 provides a serial number individualized for each device that can be read via the I2C serial interface.
Two I2C commands are required to access the device memory and retrieve the complete serial number. The
command sequence, and format of the serial number response is described in the figure below:
First access:
The format of the complete serial number is 64-bits in length, divided into 8 data bytes. The complete serial number
sequence is shown below:
The SNB3 field contains the device identification to distinguish between the different Silicon Labs relative humidity
and temperature devices. The value of this field maps to the following devices according to this table:
0x00 or 0xFF engineering samples
0x0D=13=Si7013
0x14=20=Si7020
0x15=21=Si7021
SSlaveAddress W ACK 0xFA ACK 0X0F ACK
SSlaveAddress R ACK
SNA_3 ACK CRC ACK SNA_2 ACK CRC ACK
SNA_1 ACK CRC ACK SNA_0 ACK CRC NACK P
2nd access:
SSlaveAddress W ACK 0xFC ACK 0xC9 ACK
SSlaveAddress R ACK
SNB_3 ACK SNB_2 ACK CRC ACK
SNB_1 ACK SNB_0 ACK CRC NACK P
SNA_3 SNA_2 SNA_1 SNA_0 SNB_3 SNB_2 SNB_1 SNB_0
Si7013-A20
Rev. 1.3 33
6. Control Registers
Table 21. Register Summary
Register Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
User Register 1 RES1 VDDS RSVD HTRE RSVD RES0
User Register 2 NO_HOLD THERM
_CORR
CONV_
TIME
RSVD VIN_BUF VREFP VOUT
User Register 3 RSVD HEATER[3:0]
Notes:
1. Any register not listed here is reserved and must not be written.The result of a read operation on these registers is
undefined.
2. Except where noted, reserved register bits always read back as "1", and are not affected by write operations. For future
compatibility, it is recommended that prior to a write operation, registers should be read. Then the values read from the
RSVD bits should be written back unchanged during the write operation.
Si7013-A20
34 Rev. 1.3
6.1. Register Descriptions
Reset Settings = 0011_1010
Register 1. User Register 1
Bit D7 D6 D5 D4D3D2 D1 D0
Name RES1 VDDS RSVD HTRE RSVD RES0
Type R/W R R/W R/W R/W R/W
Bit Name Function
D7; D0 RES[1:0] Measurement Resolution:
RH Temp
00: 12 bit 14 bit
01: 8 bit 12 bit
10: 10 bit 13 bit
11: 11 bit 11 bit
D6 VDDS VDD Status:
0: VDD OK
1: VDD Low
The minimum recommended operating voltage is 1.9 V. A transi-
tion of the VDD status bit from 0 to 1 indicates that VDD is
between 1.8 V and 1.9 V. If the VDD drops below 1.8 V, the
device will no longer operate correctly.
D5, D4, D3 RSVD Reserved
D2 HTRE 1 = On-chip Heater Enable
0 = On-chip Heater Disable
D1 RSVD Reserved
Si7013-A20
Rev. 1.3 35
Reset Settings = 0000_100x
Register 2. User Register 2
BitD7D6 D5 D4D3D2D1D0
Name RSVD NO_HOLD THERM
_CORR
CONV_
TIME
RSVD VIN_BUF VREFP VOUT
Type R/W R/W R/W R/W R/W R/W R/W R/W
Bit Name Function
D7 RSVD Reserved
D6 NO_HOLD 1: Auxiliary voltage and thermistor measurements made in No Hold
Master Mode. Note that this bit must be set to "0" before initiating an
internal temperature or humidity measurement.
0: Auxiliary voltage and thermistor measurements made in Hold Master
Mode.
D5 THERM_CORR 1: Thermistor correction enabled for auxiliary voltage and thermistor
measurements. Note that this bit must be set to "0" before initiating an
internal temperature or humidity measurement.
0: Thermistor correction disabled.
D4 CONV_TIME Conversion Time. Selects conversion time and noise floor of the
voltage ADC.
0: Normal mode
1: Fast mode
D3 RSVD Reserved
D2 VIN_BUF 0: VINN and VINP inputs are unbuffered
1: VINN and VINP inputs are buffered
D1 VREFP 0: A/D reference source is internal 1.25V
1: A/D reference source is VDDA
D0 VOUT* 0: VOUT pin is set to GNDD
1: VOUT pin is set to VDDD
Note: Default is powerup state of VOUT pin
*Note: VOUT is generally used for driving an external thermistor interface. Default setting is the same as the power up
setting.
Si7013-A20
36 Rev. 1.3
Reset Settings = 0000_0000
Register 3. User Register 3
BitD7D6D5D4D3D2D1D0
Name RSVD Heater [3:0]
Type R/W R/W
Bit Name Function
D3:D0 HEATER[3:0] D3 D2 D1 D0 Heater Current
0000
3.09 mA
0001
9.18 mA
0010
15.24 mA
...
0100
27.39 mA
...
1000
51.69 mA
...
1 1 1 1 94.20 mA
D7,D6,
D5,D4
RSVD Reserved
Si7013-A20
Rev. 1.3 37
7. Pin Descriptions: Si7013 (Top View)
Pin Name Pin # Pin Description
SDA 1 I2C data.
AD0/VOUT 2 Dual function pin.
This pin can be switched high or low and is generally used to drive an external
thermistor interface.
On powerup, this pin acts as a device address select pin. Tie high or low to set device
address LSB.
See Figure 5 and Figure 6.
GNDD 3 Digital ground. This pin is connected to ground on the circuit board.
GNDA 4 Analog ground. This pin is connected to ground on the circuit board.
VSNS 5 Voltage Sense Input. Tie to VDD.*
VINP 6 Analog to digital converter positive input.
VINN 7 Analog to digital converter negative input.
VDDA 8 Analog power. This pin is connected to power on the circuit board.
VDDD 9 Digital power. This pin is connected to power on the circuit board.
SCL 10 I2C clock
TGND Paddle This pad is connected to GND internally. This pad is the main thermal input to the on-
chip temperature sensor. The paddle should be soldered to a floating pad.
*Note: VSNS must be high at power up or device will be held in reset.
SDA
GNDD
VSNS
AD0/VOUT
GNDA
VINP
VDDD
SCL
VINN
VDDA
1
2
3
4
56
7
8
9
10
Si7013-A20
38 Rev. 1.3
8. Ordering Guide
Table 22. Device Ordering Guide
P/N Description Max. Accuracy Pkg Operating
Range (°C) Protective
Cover Packing
Format
Temp RH
Si7013-A20-GM Digital temperature/ humidity sensor ±0.4 °C ± 3% DFN 10 –40 to +85 °C N Cut Tape
Si7013-A20-GMR Digital temperature/ humidity sensor ±0.4 °C ± 3% DFN 10 –40 to +85 °C N Tape
& Reel
Si7013-A20-GM1 Digital temperature/ humidity sensor ±0.4 °C ± 3% DFN 10 –40 to +85 °C Y Cut Tape
Si7013-A20-GM1R Digital temperature/ humidity sensor ±0.4 °C ± 3% DFN 10 –40 to +85 °C Y Tape &
Reel
Si7013-A20-IM Digital temperature/ humidity sensor—
industrial temp range
±0.4 °C ± 3% DFN 10 –40 to +125 °C N Cut Tape
Si7013-A20-IMR Digital temperature/ humidity sensor—
industrial temp range
±0.4 °C ± 3% DFN 10 –40 to +125 °C N Tape &
Reel
Si7013-A20-IM1 Digital temperature/ humidity sensor—
industrial temp range
±0.4 °C ± 3% DFN 10 –40 to +125 °C Y Cut Tape
Si7013-A20-IM1R Digital temperature/ humidity sensor—
industrial temp range
±0.4 °C ± 3% DFN 10 –40 to +125 °C Y Tape &
Reel
Si7013-A20-YM0 Digital temperature/ humidity sensor—
automotive
±0.4 °C ± 3% DFN 10 –40 to +125 °C N Cut Tape
Si7013-A20-YM0R Digital temperature/ humidity sensor—
automotive
±0.4 °C ± 3% DFN 10 –40 to +125 °C N Tape &
Reel
Si7013-A20-YM1 Digital temperature/ humidity sensor—
automotive
±0.4 °C ± 3% DFN 10 –40 to +125 °C Y Cut Tape
Si7013-A20-YM1R Digital temperature/ humidity sensor—
automotive
±0.4 °C ± 3% DFN 10 –40 to +125 °C Y Tape
& Reel
Note: The "A" denotes product revision A and "20" denotes firmware revision 2.0.
Si7013-A20
Rev. 1.3 39
9. Package Outline
9.1. Package Outline: 3x3 10-pin DFN
Figure 11 illustrates the package details for the Si7013. Table 22 lists the values for the dimensions shown in the
illustration.
Figure 11. 10-pin DFN Package Drawing
Table 23. 10-Pin DFN Package Dimensions
Dimension Min Nom Max Dimension Min Nom Max
A 0.70 0.75 0.80 H2 1.39 1.44 1.49
A1 0.00 0.02 0.05 L 0.50 0.55 0.60
b 0.18 0.25 0.30 aaa 0.10
D 3.00 BSC. bbb 0.10
D2 1.20 1.30 1.40 ccc 0.05
e 0.50 BSC. ddd 0.10
E 3.00 BSC. eee 0.05
E2 2.40 2.50 2.60 fff 0.05
H1 0.85 0.90 0.95
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.
Si7013-A20
40 Rev. 1.3
9.2. Package Outline: 3x3 10-pin DFN with Protective Cover
Figure 12 illustrates the package details for the Si7013 with the optional protective cover. Table 23 lists the values
for the dimensions shown in the illustration.
Figure 12. 10-pin DFN with Protective Cover
Table 24. 10-pin DFN with Protective Cover Diagram Dimensions
Dimension Min Nom Max Dimension Min Nom Max
A 1.21 F1 2.70 2.80 2.90
A1 0.00 0.02 0.05 F2 2.70 2.80 2.90
A2 0.70 0.75 0.80 h 0.76 0.83 0.90
b 0.18 0.25 0.30 L 0.50 0.55 0.60
D 3.00 BSC. R1 0.45 0.50 0.55
D2 1.20 1.30 1.40 aaa 0.10
e 0.50 BSC. bbb 0.10
E 3.00 BSC. ccc 0.05
E2 2.40 2.50 2.60 ddd 0.10
eee 0.05
Notes:
1. All dimensions shown are in millimeters (mm).
2. Dimensioning and Tolerancing per ANSI Y14.5M-1994.
Si7013-A20
Rev. 1.3 41
10. PCB Land Pattern and Solder Mask Design
Table 25. PCB Land Pattern Dimensions
Symbol mm
C1 2.80
E0.50
P1 1.40
P2 2.60
X1 0.30
Y1 1.00
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 2x1 array of 0.95 mm square openings on 1.25 mm pitch should be used for the
center ground pad to achieve a target solder coverage of 50%.
Card Assembly
8. The recommended card reflow profile is per the JEDEC/IPC J-STD-020 specification
for Small Body Components.
Si7013-A20
42 Rev. 1.3
11. Top Marking
11.1. Si7013 Top Marking
11.2. Top Marking Explanation
Mark Method: Laser
Pin 1 Indicator: Circle = 0.30 mm Diameter
Upper-Left Corner
Font Size: 0.30 mm
Line 1 Marking: TTTT = Mfg Code
Si7013-A20
Rev. 1.3 43
12. Additional Reference Resources
AN607: Si70xx Humidity Sensor Designer’s Guide
Si7013-A20
44 Rev. 1.3
DOCUMENT CHANGE LIST
Revision 0.9 to Revision 0.91
Updated Table 2 on page 4.
Revision 0.91 to Revision 1.0
Updated document revision to 1.0.
Revision 1.0 to Revision 1.1
Updated Footnote 2 in Table 3 on page 5
Updated Section “4.5. Protecting the Sensor”
Updated Table 12 on page 19
Corrected a typo in the I2C sequence for no-hold
mode in Section “5. I2C Interface”
Corrected a typo in Table 15 on page 22
Updated Table 24 on page 40 dimensions F1 and F2
Revision 1.1 to Revision 1.2
February 16, 2016
Added notes in Section 5.4 that device must be
power cycled before external voltage measurement
coefficients will take effect.
Corrected error in thermistor calculation formula
(changed 46.4k to 48.6k).
Revision 1.2 to Revision 1.3
June, 2016
Updated diagram in "5.5. Firmware Revision" on
page 31.
Updated "8. Ordering Guide" on page 38 with correct
package type.
Updated notes in Table 25, “PCB Land Pattern
Dimensions,” on page 41.
Changed packing format from tube to cut tape for all
non-tape & reel part numbers without protective filter
covers.
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