What this steering array does that a TVS diode can't
The Texas Instruments TPD4S009DBVRG4 is a four-channel rail-to-rail steering diode array designed to shunt ESD strikes on high-speed differential pairs like Ethernet and HDMI. Unlike a standalone TVS, the steering architecture directs the transient to the supply rail or ground through low-capacitance diodes, preserving signal integrity at data rates where a TVS's junction capacitance would round the edges. The 25W peak pulse power rating tells you this is for ESD events (IEC 61000-4-2), not power-line surges — the 5.5V reverse standoff and 9V minimum breakdown keep it transparent on 3.3V and 5V interfaces.
Four channels, one small footprint
The SOT-23-6 package packs four unidirectional channels into a footprint smaller than two discretes. That saves board area on HDMI or Ethernet ports where you need per-pair protection.