USB-Serial: I2C Lines Pull-Up Resistor – KBA89374

Version 1
    Version: *A

     

    Question: Do you have to connect the external pull-up resistors for the I2C lines of a USB-Serial Bridge Controller device?

     

    Answer:

    Yes, the SCLK and SDATA lines of the I2C interface of the USB-Serial Bridge Controller device are open drain pins. External pull-up resistors must be connected on these I2C lines. These pull-up resistors should be connected to the VDDD supply. Recommended values for the pull-up resistors are shown in Table 1.

    Table 1. Recommended Values for the Pull-up Resistors

                                                                  
         I2C Operating Frequency     Resistor Value
         100 kHz     4.7 KΩ
         400 kHz     2.2 KΩ