SCPS221G October 2010 – November 2018 TCA9406
Each A-port I/O has an internal 10-kΩ pullup resistor to VCCA, and each B-port I/O has an internal 10-kΩ pullup resistor to VCCB. If a smaller value of pullup resistor is required, an external resistor must be added from the I/O to VCCA or VCCB (in parallel with the internal 10-kΩ resistors). Adding lower value pullup resistors will effect VOL levels, however. The internal pullups of the TCA9406 are disabled when the OE pin is low.