SI7005EVB-UDP 查看數據表（PDF） - Silicon Laboratories
零件编号
产品描述 (功能)
生产厂家
SI7005EVB-UDP Datasheet PDF : 40 Pages
| |||
Si7005
6. Si7005 Connection Diagrams
The Si7005 is a simple-to-use device requiring a minimum of external components. Figure 9 shows the typical
connection diagram for the Si7005 connected to an MCU. (Refer to section “8. Pin Descriptions: Si7005” for full pin
descriptions). The values for the two I2C pull-up resistors depend on the capacitance of the I2C bus lines and the
desired speed of operation. Refer to the I2C specification for further details. In this diagram CS is shown controlled
by the MCU, allowing the Si7005 to be placed in standby mode when not in use. A detailed schematic and bill-of-
materials for this circuit can be found in section “2. Typical Application Circuits” and section “3. Bill of Materials”.
2.1 to 3.6 V
0.1 µF
VDD
SCL
Si7005
SDA
CEXT
CS
GND
4.7µF
VDD
SCL
SDA
Px.x
MCU
C8051Fxxx
GND
Figure 9. Typical Connection Diagram
For ultra-low-power operation, such as in battery-powered applications, connection as shown in Figure 10 is
recommended. In this case, the Si7005 is powered from one of the MCU’s GPIOs. The GPIO can be driven high to
powerup the Si7005, once the measurement results are obtained, the GPIO can be driven low to power-down the
Si7005, reducing its current consumption to zero. The GPIO must be capable of sourcing 320 µA for the duration of
the conversion time (<200 ms for relative humidity and temperature conversions) and up to 40 mA for a period of
5 ms at power-up. The GPIO must also be capable of sinking up to 40 mA for a period of 5 ms at powerdown. If the
GPIO is not capable of sourcing/sinking 40 mA, then the Si7005 will take longer to powerup and powerdown. The
purpose of the 15 resistor is to isolate the Si7005 from potential high-frequency switching noise present on the
MCU GPIO. A detailed schematic and bill-of-materials for this circuit can be found in section “2. Typical Application
Circuits” and section “3. Bill of Materials”.
Rev. 1.3
25
Share Link: 