Si 7 0 1 3 - A20 I 2 C H UMIDITY A N D TW O - Z ONE TEMPERATURE S ENSOR Features 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 A 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 Ordering Information: See page 38. Pin Assignments Applications HVAC/R Thermostats/humidistats Instrumentation White goods Micro-environments/data centers Industrial Controls Indoor weather stations Top View 1 10 AD0/VOUT 2 9 VDDD GNDD 3 8 VDDA GNDA 4 7 VINN VSNS 5 6 VINP SDA 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. SCL Patent Protected. Patents pending 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. Rev. 1.3 8/16 Copyright (c) 2016 by Silicon Laboratories Si7013-A20 Si7013-A20 Functional Block Diagram VSNS Vdd 1.25V Ref Calibration Memory Si7013 Humidity Sensor AD0/VOUT Temp Sensor VINP VINN Control Logic ADC Analog Input I2C Interface GND 2 Rev. 1.3 SDA SCL Si7013-A20 TABLE O F C ONTENTS 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 Rev. 1.3 3 Si7013-A20 1. Electrical Specifications Unless otherwise specified, all min/max specifications apply over the recommended operating conditions. Table 1. Recommended Operating Conditions Parameter Symbol Power Supply Test Condition VDD Min Typ Max Unit 1.9 -- 3.6 V Operating Temperature TA I and Y grade -40 -- +125 C Operating Temperature TA G grade -40 -- +85 C Table 2. General Specifications 1.9 < VDD < 3.6 V; TA = -40 to 85 C (G grade) or -40 to 125 C (I/Y grade); default conversion time unless otherwise noted. 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 A Parameter VSNS pin (200K nominal pull up); Vin = GND Output Voltage Low Output Voltage High VOL VOH IDD -- -- 0.6 V SDA pin; IOL = 1.2 mA; VDD = 1.9 V -- -- 0.4 V -- -- V VDD- 0.1 -- -- V VOUT pin, IOH = -1.7 mA, VDD = 3.0 V VDD - 0.4 RH conversion in progress -- -- -- V 150 180 A -- 90 120 A VOUT pin, IOH = -0.5 mA, VDD = 2.0 V VDD - 0.2 Temperature conversion in progress Standby, -40 to +85 C2 Standby, -40 to +125 C -- 0.06 0.62 A 2 -- 0.06 3.8 A 3 -- 3.5 4.0 mA -- 3.5 4.0 mA -- 3.1 to 94.2 -- mA Peak IDD during powerup Peak IDD during I2C operations4 Heater Current 5 A SDA pin; IOL = 2.5 mA; VDD = 3.3 V VOUT pin, IOH = -10 A Current Consumption 5xVDD IHEAT 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 s for all commands except Measure Analog Voltage or Thermistor Temperature, which has <150 s duration when Thermistor Correction is enabled. 5. Additional current consumption when HTRE bit enabled. See Section "5.6. Heater" for more information. 4 Rev. 1.3 Si7013-A20 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 Conversion Time1 Powerup Time Symbol Test Condition Min Typ Max tCONV 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 From VDD 1.9 V to ready for a conversion, 25 C -- 18 25 ms From VDD 1.9 V to ready for a conversion, full temperature range -- -- 80 ms After issuing a software reset command -- 5 15 ms tPU Unit ms Notes: 1. Initiating a RH measurement will also automatically initiate a temperature measurement. The total conversion time will be tCONV(RH) + tCONV(T). 2. No conversion or I2C transaction in progress. Typical values measured at 25 C. 3. Occurs once during powerup. Duration is <5 msec. 4. Occurs during I2C commands for Reset, Read/Write User Registers, Read EID, Read Firmware Version, Read/Write Thermistor Coefficients and Measure Analog Voltage or Thermistor Temperature. Duration is <50 s for all commands except Measure Analog Voltage or Thermistor Temperature, which has <150 s duration when Thermistor Correction is enabled. 5. Additional current consumption when HTRE bit enabled. See Section "5.6. Heater" for more information. 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 Frequency2 fSCL -- -- 400 kHz SCL High Time tSKH 0.6 -- -- s 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 s. 3. Pulses up to and including 50 ns will be suppressed. Rev. 1.3 5 Si7013-A20 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 SCL Low Time tSKL 1.3 -- -- s Start Hold Time tSTH 0.6 -- -- s Start Setup Time tSTS 0.6 -- -- s Stop Setup Time tSPS 0.6 -- -- s Bus Free Time tBUF 1.3 -- -- s 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 s tVD;ACK From SCL low to data valid -- -- 0.9 s 50 -- -- ns SDA Acknowledge Valid Time 3 Suppressed Pulse Width Between Stop and Start tSP 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 s. 3. Pulses up to and including 50 ns will be suppressed. tSKH 1/fSCL tSKL tSP SCL tBUF tSTH tDS D6 SDA D5 tDH D4 D0 tSPS R/W ACK Start Bit Stop Bit tVD : ACK tSTS Figure 1. I2C Interface Timing Diagram 6 Rev. 1.3 Si7013-A20 Table 4. Humidity Sensor 1.9 VDD 3.6 V; TA = 30 C; default conversion time unless otherwise noted. Parameter Symbol 1 Operating Range Accuracy2, 3 Test Condition Min Typ Max Unit Non-condensing 0 -- 100 %RH 0 - 80% RH -- 2 3 %RH 80 - 100% RH Repeatability-Noise See Figure 2. %RH 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 1 m/s airflow, with cover -- 18 -- 1 m/s airflow, without cover -- 17 -- Drift vs. Temperature -- 0.05 -- %RH/C Hysteresis -- 1 -- %RH -- < 0.25 -- %RH/yr Response Time4 63% 3 Long Term Stability S Notes: 1. Recommended humidity operating range is 20% to 80% RH (non-condensing) over -10 C to 60 C. Prolonged operation beyond these ranges may result in a shift of sensor reading with slow recovery time. 2. Excludes hysteresis, long term drift, and certain other factors and is applicable to non-condensing environments only. See Section "4.1. Relative Humidity Sensor Accuracy" for more details. 3. Drift due to aging effects at typical room conditions of 30C 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. Rev. 1.3 7 Si7013-A20 Figure 2. RH Accuracy at 30 C 8 Rev. 1.3 Si7013-A20 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 I and Y Grade -40 -- +125 C G Grade -40 -- +85 C -10 C < tA < 85 C -- 0.3 0.4 C Operating Range Accuracy1 -40 C < tA < 125 C Repeatability-Noise Response Time2 63% Figure 3. C 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 Unmounted device -- 0.7 -- s Si7013-EB board -- 5.1 -- s -- < 0.01 -- Long Term Stability C/Yr Notes: 1. 14b measurement resolution (default). 2. Time to reach 63% of final value in response to a step change in temperature. Actual response time will vary dependent on system thermal mass and airflow. Figure 3. Temperature Accuracy* *Note: Applies only to I and Y devices beyond +85 C. Rev. 1.3 9 Si7013-A20 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 = 1.25 V internal or VDDA, buffered and unbuffered mode, unless otherwise noted. Parameter Symbol Test Condition Resolution Min Typ Max Unit -- VREF/ 32768 -- V Integral Non-linearity INL |VINP-VINN| < VREF/2 -- 1 -- LSB Differential Non-linearity DNL |VINP-VINN| < VREF/2 -- 1 -- LSB N |VINP-VINN| < VREF/2, VREF = 1.25 V, Normal Mode -- 25 -- VRMS |VINP-VINN| < VREF/2, VREF = 1.25 V, Fast Mode -- 50 -- Noise Input Offset (Buffered Mode) VOS |VINP-VINN| = 0 -- -- 10 mV Input Offset (Unbuffered Mode)1,2 VOS |VINP-VINN| = 0 -- -- 1 mV Gain Accuracy G VREF = 1.25 V; gain is absolute -- +1 +2 % VREF = VDD; 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. 10 Rev. 1.3 Si7013-A20 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 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 HBM -- -- 2 kV CDM -- -- 1.25 kV MM -- -- 250 V ESD Tolerance Symbol Test Condition 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. Rev. 1.3 11 Si7013-A20 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. WR9 ) N 9''' 9''$ 6&/ 6L N 6'$ 9616 $'9287 6&/ 6'$ 9,13 9,11 *1'' *1'$ 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. 1.9V to 3.6V C1 0.1F 8 6 VINP TH1 10k NTC Si7013 7 C3 0.1F 9 VDDA VDDD SCL R3 24k C2 0.1F R1 R2 10k 10k 10 SCL SDA 1 SDA VSNS 5 VINN R4 24k 2 AD0/VOUT GNDD GNDA 3 4 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 12 Rev. 1.3 Si7013-A20 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. 1.9 to 3.6V C1 0.1F 8 2 C2 0.1F R3 24k 6 9 AD0/VOUT VDDA VDDD SCL Si7013 7 10 SCL SDA 1 SDA VSNS 5 VINP TH1 10k NTC R1 R2 10k 10k VINN R4 24k GNDD GNDA 3 4 Figure 6. Typical Application Circuit for Thermistor Interface with AD0 = 0 WR9 & ) 9WR9 9ROWDJH,QSXW 5 N 9,13 9,11 5 N 9''$ 9''' 6&/ 6&/ 6'$ 6'$ 9616 5 N 5 N 6L $'9287 *1'' *1'$ 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. Rev. 1.3 13 Si7013-A20 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 F, 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 F, 16 V, X7R, 0603 C0603X7R160-104M Venkel C2 Capacitor, 0.1 F, 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 14 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 F, 16 V, X7R, 0603 C0603X7R160-104M Venkel U1 IC, Digital Temperature/humidity Sensor Si7013-A20 Silicon Labs Rev. 1.3 Si7013-A20 4. Functional Description VSNS Vdd 1.25V Ref Calibration Memory Si7013 Humidity Sensor AD0/VOUT Temp Sensor VINP VINN Control Logic ADC Analog Input I2C Interface SDA SCL GND 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. Rev. 1.3 15 Si7013-A20 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 of factory calibration Margin for shifts that can occur during solder reflow Accuracy The accuracy specification does not include: Hysteresis (typically 1%) 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 Effects 16 Rev. 1.3 Si7013-A20 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 KaptonKPPD-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. Rev. 1.3 17 Si7013-A20 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(R) 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 18 Rev. 1.3 Si7013-A20 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 IP Rating (per IEC 529) 260 C IP67 Rev. 1.3 19 Si7013-A20 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. 20 Rev. 1.3 Si7013-A20 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. Table 13. I2C Slave Address Byte A6 A5 A4 A3 A2 A1 A0 R/W 1 0 0 0 0 0 AD0 1/0 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 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 Rev. 1.3 21 Si7013-A20 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. 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). In the I2C sequence diagrams in the following sections, bits produced by the master and slave are color coded as shown: Master 22 Slave Rev. 1.3 Si7013-A20 *Note: Device will NACK the slave address byte until conversion is complete. Rev. 1.3 23 Si7013-A20 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: RH_Code %RH = 125 ---------------------------------------6 65536 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 outside 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: 175.72 Temp_Code- - 46.85 Temperature (C = ------------------------------------------------------65536 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. 24 Rev. 1.3 Si7013-A20 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. Sequence to read a register Slave S Address W Slave Read Reg A A Cmd Sr Addres R A s Read Data NA P Sequence to write a register S Slave Address W Write Reg A Cmd A Write Data A P 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. Table 16. Analog Input Ranges VINP Input Range Buffered Input Unbuffered Input VINN Input Range Min Max Min Max 0.35 V VDD-0.35 V 0.35 V VDD-0.35 V 0V VDD 0V VDD 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. Rev. 1.3 25 Si7013-A20 5.4. Nonlinear Correction of Voltage Inputs: The Si7013 contains a look-up table for applying non-linear correction to external voltage measurements. The lookup 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) 26 Rev. 1.3 Si7013-A20 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 Rev. 1.3 27 Si7013-A20 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. 28 Rev. 1.3 Si7013-A20 5.4.3. Example Thermistor Calculations For the Si7013 evaluation board with a 10 K ohm thermistor and two 24.3 Kbias 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 Rev. 1.3 29 Si7013-A20 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 4F 95 67 A7 3B 96 3C A8 32 97 F8 A9 2B 98 4B AA B3 99 8A AB 1F 9A 5A AC 2E 9B 1B AD 15 9C 68 AE D8 9D Ad AF F 9E 77 B0 37 9F 3F B1 A A0 85 B2 A1 A1 D0 B3 7 A2 94 B4 7C A3 62 B5 5 A4 A2 B6 57 A5 F3 B7 83 84 15154 85 86 11187 87 88 7982 89 8A 5592 8B 8C 3895 8D 8E 2721 8F 90 1916 91 92 93 30 1367 15608 19338 23067 26797 30527 34256 37986 41715 Rev. 1.3 26 -241 FF 0F -298 FE D6 -400 FE 70 -563 FD CD -813 FC D3 -1186 FB 5E -1739 F9 35 -2513 F6 2F Si7013-A20 5.5. Firmware Revision The internal firmware revision can be read with the following I2C transaction: S Slave Address W A 0x84 R A A FWREV 0xB8 NA A S Slave Address P 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. 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 = 3.3 V. Rev. 1.3 31 Si7013-A20 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: S Slave Address W ACK S Slave Address R ACK SNA_3 ACK SNA_1 S S 0xFA ACK 0X0F ACK CRC ACK SNA_2 ACK CRC ACK ACK CRC ACK SNA_0 ACK CRC NACK Slave Address W ACK 0xFC ACK 0xC9 ACK Slave Address R ACK SNB_3 ACK SNB_2 ACK CRC ACK SNB_1 ACK SNB_0 ACK CRC NACK P 2nd access: P 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: SNA_3 SNA_2 SNA_1 SNA_0 SNB_3 SNB_2 SNB_1 SNB_0 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 32 Rev. 1.3 Si7013-A20 6. Control Registers Table 21. Register Summary Register Bit 7 Bit 6 User Register 1 RES1 VDDS User Register 2 User Register 3 NO_HOLD Bit 5 Bit 4 Bit 3 RSVD THERM _CORR CONV_ TIME RSVD RSVD Bit 2 Bit 1 Bit 0 HTRE RSVD RES0 VIN_BUF VREFP VOUT 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. Rev. 1.3 33 Si7013-A20 6.1. Register Descriptions Register 1. User Register 1 Bit D7 D6 Name RES1 VDDS Type R/W R D5 D4 D3 D2 D1 D0 RSVD HTRE RSVD RES0 R/W R/W R/W R/W Reset Settings = 0011_1010 Bit Name D7; D0 RES[1:0] D6 VDDS Function Measurement Resolution: RH 00: 12 bit 01: 8 bit 10: 10 bit 11: 11 bit VDD Status: 0: 1: Temp 14 bit 12 bit 13 bit 11 bit VDD OK VDD Low The minimum recommended operating voltage is 1.9 V. A transition 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. 34 D5, D4, D3 RSVD Reserved D2 HTRE 1 = On-chip Heater Enable 0 = On-chip Heater Disable D1 RSVD Reserved Rev. 1.3 Si7013-A20 Register 2. User Register 2 Bit D7 D6 D5 D4 D3 D2 D1 D0 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 Reset Settings = 0000_100x Bit Name Function D7 RSVD 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 D3 RSVD 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 Reserved Conversion Time. Selects conversion time and noise floor of the voltage ADC. 0: Normal mode 1: Fast mode Reserved 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. Rev. 1.3 35 Si7013-A20 Register 3. User Register 3 Bit D7 D6 D5 D4 D3 D2 Name RSVD Heater [3:0] Type R/W R/W Reset Settings = 0000_0000 Bit D3:D0 Name HEATER[3:0] Function Heater Current D3 D2 D1 D0 0 0 0 0 3.09 mA 0 0 0 1 9.18 mA 0 0 1 0 15.24 mA 0 27.39 mA 0 51.69 mA 1 94.20 mA ... 0 1 0 ... 1 0 0 ... 1 D7,D6, D5,D4 36 D1 RSVD 1 1 Reserved Rev. 1.3 D0 Si7013-A20 7. Pin Descriptions: Si7013 (Top View) SDA 1 10 AD0/VOUT 2 9 VDDD GNDD 3 8 VDDA GNDA 4 7 VINN VSNS 5 6 VINP SCL 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 onchip 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. Rev. 1.3 37 Si7013-A20 8. Ordering Guide Table 22. Device Ordering Guide P/N Description Max. Accuracy Temp RH Pkg Operating Range (C) Protective Cover Packing Format 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. 38 Rev. 1.3 Si7013-A20 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 bbb 0.10 ccc 0.05 D D2 3.00 BSC. 1.20 1.30 1.40 e 0.50 BSC. ddd 0.10 E 3.00 BSC. eee 0.05 fff 0.05 E2 2.40 2.50 2.60 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. Rev. 1.3 39 Si7013-A20 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 R1 0.45 0.50 0.55 D D2 3.00 BSC. 1.20 1.30 1.40 0.10 e 0.50 BSC. bbb 0.10 E 3.00 BSC. ccc 0.05 ddd 0.10 eee 0.05 E2 2.40 2.50 2.60 Notes: 1. All dimensions shown are in millimeters (mm). 2. Dimensioning and Tolerancing per ANSI Y14.5M-1994. 40 aaa Rev. 1.3 Si7013-A20 10. PCB Land Pattern and Solder Mask Design Table 25. PCB Land Pattern Dimensions Symbol mm C1 2.80 E 0.50 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 m 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. Rev. 1.3 41 Si7013-A20 11. Top Marking 11.1. Si7013 Top Marking 11.2. Top Marking Explanation 42 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 Rev. 1.3 Si7013-A20 12. Additional Reference Resources AN607: Si70xx Humidity Sensor Designer's Guide Rev. 1.3 43 Si7013-A20 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. 44 Rev. 1.3 Smart. Connected. Energy-Friendly Products Quality Support and Community www.silabs.com/products www.silabs.com/quality community.silabs.com Disclaimer Silicon Laboratories intends to provide customers with the latest, accurate, and in-depth documentation of all peripherals and modules available for system and software implementers using or intending to use the Silicon Laboratories products. Characterization data, available modules and peripherals, memory sizes and memory addresses refer to each specific device, and "Typical" parameters provided can and do vary in different applications. Application examples described herein are for illustrative purposes only. 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