SI7013 Datasheet, PDF (12/43 Pages) Silicon Laboratories – I2C HUMIDITY AND TWO-ZONE TEMPERATURE SENSOR

Si7013
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.
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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
C2
0.1µF
TH1
10k
NTC
C3
0.1µF
C1
0.1µF
R3
24k
6 _VINP
8
9
V_DDA
V_DDD
SCL
10
SDA ¹
Si7013
RST ⁵
7 _VINN
R4
24k
2 _AD0/VOUT
GNDD GNDA
3
4
R1 R2
10k 10k
SCL
SDA
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. 0.95