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

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