The TMUXHS4412 has a weak pulldown of 1MΩ from D[0/1/2/3][P/N] pins to GND. While these resistors biases the device data channels to common-mode voltage (CMV) of 0V with very weak strength, TI recommends that the device is biased by a stronger impedance from either side of the device to a valid value. To avoid double biasing, ensure appropriate AC coupling capacitors are on either side of the device.

In certain use cases where both sides of the TMUXHS4412 is AC-coupled, TI recommends to use appropriate CMV biasing for the device. 10kΩ to GND or any other bias voltage in the CMV range for each D[0/1/2/3][P/N] pin will suffice for most use cases.

The high-speed data ports incorporate 20kΩ pulldown resistors that are switched in when a port is not selected and switched out when the port is selected. For example: when SEL = L, the DB[0/1/2/3][P/N] pins have 20kΩ resistors to GND. The feature ensures that unselected port is always biased to a known voltage for long term reliability of the device and the electrical channel.

The positive and negative terminals of data pins D[0/1/2/3] have a weak (20kΩ) differential resistor in between the terminals for device switch regulation operation. This does not impact signal integrity or functionality of high-speed differential signaling that typically has much stronger differential impedance (such as 100Ω).