AN607

2

Rev. 1.7

2. Si70xx Monolithic Humidity and Temperature Sensors

The Si70xx family uses state-of-the-art sensing technologies to create precise monolithic humidity and temperature

sensors. Temperature is sensed by a precision Vbe referenced circuit on the die. Humidity is sensed by measuring

the capacitance change of a low-k dielectric layer applied to the surface of the die. Consequently, both temperature

and humidity are precisely measured in extremely close proximity on the same monolithic device, which is critical

for accurate dew point measurement.

The Si7005 was the first-generation sensor in a 4 mm x 4 mm package. The Si7015 is a pin-compatible upgrade

(see “AN764: Upgrading from the Si7005 to the Si7015”). The Si7006, Si7007, Si7013, Si7020, Si7021, Si7022,

and Si7023 second-generation parts come in an industry-standard 3 mm x 3 mm package. The Si7034 is available

in an industry standard 2x2 mm package.

Figure 4 shows a functional block diagram of the Si7013 humidity and temperature sensor. Very few external

optional analog input path for measurement of a remote thermistor or any other analog voltage. It also has a dual

application, the 10 k

required is the 0.1 µF power supply bypass capacitor.

Figure 4. Si7013 Functional Block Diagram

there is no hole in the package, and only the temperature sensor functionality is supported.

Refer to the data sheets (e.g., Si7013) for detailed pin descriptions, register summary, and timing details.

The Si7007, Si7022 and Si7023 parts contain pulse width modulated (PWM) outputs. On one pin, the pulse width is

proportional to temperature while the pulse width on a different pin is proportional to humidity. There is a select pin

that can be used to interchange the assignment of the outputs pins. In most applications the PWM output of these

parts is filtered to give a voltage proportional to temperature or humidity. The functional block for all the PWM

output parts is the same, and this is shown in Figure 5 for the Si7022.

ADC

HUMIDITY

SENSOR

TEMP

SENSOR

ANALOG

INPUT

DIGITAL

LOGIC

INTERFACE

Si7013

VDDD

VDDA

GNDD

GNDA

TGND

(Exposed Pad)

SDA

SCL

VSNS

AD0/VOUT

VINP

VINN

3

4

89

1

10

2

5

6

7

1.25V

REF