What the 14 mOhm Rds(on) means for your 5 A rail
The TPS22953DSQR is a single-channel high-side N-channel load switch from Texas Instruments, rated for 5 A continuous output across a 2.5 V to 5.7 V load voltage range. The 14 mOhm typical on-resistance sets the conduction loss at 0.35 W at full load — that heat must be sunk through the 10-WSON exposed pad to a copper plane, or the junction temperature climbs above the 105 °C operating limit. The switch is controlled by a single On/Off input with non-inverting logic; no external Vcc supply is needed — the gate drive is generated from the input voltage itself, which simplifies the BOM but limits the input range to the 2.5–5.7 V window.
Three fault protections that decide the restart behaviour
The TPS22953DSQR integrates over-temperature shutdown, reverse-current blocking, and undervoltage lockout. The reverse-current protection is the standout — when the output bus is back-driven (e.g., from a charged capacitor or another supply), the switch opens to prevent current flowing from output to input, which protects the upstream rail. The UVLO threshold holds the switch off until the input voltage is high enough to fully enhance the N-channel FET, avoiding partial turn-on that would dissipate excessive power. Auto-restart means the switch re-enables after a fault condition clears — useful for hot-swap or USB power delivery where a momentary over-current is expected, but a hard short will cause the switch to cycle on and off until the fault is removed. The slew-rate controlled turn-on limits inrush current into capacitive loads, which is critical when the load includes bulk decoupling capacitors.
Package and thermal: the 2x2 mm WSON footprint
The 10-WFDFN exposed pad package is supplied as the 10-WSON (2x2 mm) variant. At 5 A and 14 mOhm, the 0.35 W dissipation raises the junction above ambient by roughly 35–40 °C with a good thermal land; in a 85 °C ambient that puts the junction near the 105 °C limit, so the layout is not optional. CT is available for prototype or low-volume builds.
Active production — no end-of-life watch
The base product number TPS22953 is a current TI catalog line, so the DSQR suffix is a standard reel option. ROHS3 compliant.