Load switch for battery-powered portable gear
The TCK22971G,LF is a single-channel, high-side P-Channel load switch from Toshiba, designed to enable or disable power rails in portable electronics where board space is tight and on-resistance matters. It handles up to 2 A continuous output across a load voltage range of 1.1 V to 5.5 V, with a typical Rds(on) of 25 mOhm — low enough that at 2 A the conduction loss stays under 100 mW, so the WLCSP package doesn't need a copper pour to stay cool. The switch is controlled by a simple On/Off logic input (non-inverting), and no external Vcc supply is required — the gate drive is derived from the load rail itself.
Slew-rate control and reverse-current blocking
Slew rate controlled switching means the output voltage ramps up gradually when the enable pin goes high — this limits inrush current into downstream decoupling caps and prevents the upstream rail from dipping during power-up. Built-in reverse current protection blocks current flow from the output back to the input when the switch is off, which is useful in multi-rail systems where one rail might stay live while another is gated.
WLCSP-6 package — board-fit considerations
The device comes in a 6-bump WLCSP (0.80 x 1.2 mm body) — the 0.4 mm pitch and exposed bumps mean the PCB land pattern must match the Toshiba recommended footprint exactly to avoid solder bridging and ensure reliable contact. Because it's a wafer-level chip-scale package, the MSL rating is typically MSL-1 (no moisture sensitivity bake required before reflow), but verify the reel label — if it's MSL-3 or higher, bake it before the oven or it popcorns.