Si7013-A20-IM - Silicon Labs

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

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

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

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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GNDD

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SCL

SDA

Si7013

SCL

SDA

1.9V to 3.6V

AD0/VOUT

VINP

VINN

0.1µF

24k

TH1

10k

NTC

VDDA

GNDA

VSNS

10k

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.

0.1µF

GNDD

VDDD

SCL

SDA

Si7013

SCL

SDA

1.9 to 3.6V

AD0/VOUT

VINP

VINN

0.1µF R3

24k

VDDA

GNDA

VSNS

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 kNTCLE100E3103 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.

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

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 125RH_Code

65536

--------------------------------------- 6–=

Temperature (C175.72Temp_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

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.

Sequencetoreadaregister

SSlave

Address WAReadReg

Cmd ASr

Slave

Addres

R A Read

Data

NA P

Sequencetowritearegister

SSlave

Address WAWriteReg

Cmd AWriteData 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

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

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

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:

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

SSlaveAddress W ACK 0xFA ACK 0X0F ACK

SSlaveAddress 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:

SSlaveAddress W ACK 0xFC ACK 0xC9 ACK

SSlaveAddress 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

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

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

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

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

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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device, and "Typical" parameters provided can and do vary in different applications. Application examples described herein are for illustrative purposes only. Silicon Laboratories

reserves the right to make changes without further notice and limitation to product information, specifications, and descriptions herein, and does not give warranties as to the accuracy

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