400 mOhm Rds(on) — voltage drop at the rail edge
The TPS22943DCKR is a single-channel, high-side P-channel load switch from Texas Instruments, designed for general-purpose power-rail sequencing and distribution. The typical on-resistance of 400 mOhm produces a 16 mV drop at the 40 mA maximum output current — negligible on a 3.3 V rail but worth checking at the 1.62 V minimum, where the drop consumes about 1% of the headroom.
Integrated protection — fixed current limit, OTP, UVLO
The switch integrates fixed current limiting, over-temperature protection, and under-voltage lockout (UVLO). The current limit is not adjustable, so the designer must verify that the load inrush does not trip the limit during startup. The UVLO holds the switch off until the input voltage rises above the threshold, preventing partial-on states during power ramp. These protections eliminate the need for a separate supervisor or current-sense resistor on the output.
The SC-70-5 package (also known as SOT-353) keeps the footprint small — 2.0 mm × 2.1 mm — suiting space-constrained boards in motor drives, outdoor telecom, and engine-bay modules.