I3C Controllers manage an active (such as, dynamic) pull-up resistance on SDA, which they can enable and disable as the bus transitions between open drain and push-pull mode. The continuous DC current sourcing or sinking capability is determined by the external system-level open-drain or push-pull drivers that are interfaced to the TCA39416 I/O pins.

In TCA39416, each A-port I/O has an internal 10-kΩ pull up resistor to V_CCA, and each B-port I/O has an internal 10-kΩ pull up resistor to V_CCB. The internal pull ups of the TCA39416 are controlled by their respective supplies. The resistors have back-biasing protection, so that if a supply is off, the current cannot flow through the resistors back into the supply. When both A and B side supply is above V_{UVLO_RISE} and OE is high, the pull up resistors are enabled when the bus is high.