Level Shifter Board to Connect an SHTW2 to Atmel Xplained Pro
The SHTW2 is designed for a 1.8V supply voltage (1.62..1.98V). To use it with a 5V I2C bus, level shifters are needed. This tutorial describes how to build such a board.
While this is written with Atmel Xplained in mind, the same concept can be used to integrate with any board that has a higher I2C bus voltage than 1.98V (for example most Arduino boards and Raspberry Pi).
Bill of Material
|Voltage Regulator IC||Linear Voltage Regulator IC Positive Fixed 1 Output 1.8V 150mA||Linear Voltage Regulator IC Positive Fixed 1 Output 1.8V 150mA SC-82AB|
|Level Shifters||Level Shifters for I2C communication||MOSFET N-CH 20V .2A EMT3|
Schema for Assembly
Attach to Atmel D20 Board as Extension
Connect the components as described in the schema above or build your own PCB accordingly. Then connect the SCL and SDA pins to the Atmel D20 Xplained Pro platform's pin 11 and 12 for the I2C communication. The SCL_LS and SDA_LS can be used to connect with the Flex PCB of the SHTW2 sensor.
|11||I2C_SDA||Data line for I2C interface. Always implemented, bus type.|
|12||I2C_SCL||Clock line for I2C interface. Always implemented, bus type.|
The VCC and GND of the Flex PCB are connected to the LDO's output 1V8 and GND and the pins 19 and 20 are connected to the LDO's input GND and VCC, respectively.
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