Why the 47 mOhm Rds(on) and 3 A rating matter for your USB port
The TPS2549IRTERQ1 is a single-channel high-side USB power switch from Texas Instruments, built for automotive USB ports where the load is a phone or tablet charging at up to 3 A. The 47 mOhm typical on-resistance means the voltage drop across the switch at 3 A is roughly 140 mV — low enough to keep the output above 4.75 V from a 5 V rail, which is the USB 2.0 minimum for a high-power port. The 4.5 V to 6.5 V load supply range covers the 5 V nominal bus plus the dips during engine cranking without dropping out.
Fault protection set — adjustable current limit, OVP, UVLO, thermal shutdown
The switch integrates adjustable current limiting, over-voltage protection, under-voltage lockout, and over-temperature shutdown. The current limit is set with an external resistor, so you can tailor the trip point to the cable impedance and downstream device. OVP clamps the output if the input bus spikes above the normal range — a real risk on automotive power rails during load dump or alternator ripple. UVLO holds the switch off until the input rises above the 4.5 V threshold, preventing the switch from operating in a brownout condition.
Active production — sourcing posture for this automotive-grade part
The package is a 16-WFQFN with an exposed pad, 3 mm x 3 mm, tape-and-reel or cut-tape options.
Package and footprint — 16-WQFN with exposed pad
The supplier device package is 16-WQFN (3x3 mm) with an exposed pad. The package is surface-mount only; no through-hole variant exists.