PCMCIA power switch — four slots, three control lines
The TPS2228PWPR: Its 3:4 input-to-output ratio means three control signals manage four high-side switches, each rated for 1 A continuous output.
97 mOhm Rds(on) — what it buys the slot power budget
At 1 A per output, the 97 mOhm typical Rds(on) produces under 100 mW of conduction loss per channel. The fixed current-limiting and over-temperature fault protection prevent the switch from exceeding its SOA during a card short or stalled fan.
Obsolete — sourcing reality for sustainment programs
Status flag output — what it signals to the host controller
The Status Flag feature provides a digital open-drain output that asserts low when the switch enters current-limit or thermal-shutdown. The host PCMCIA controller reads this flag to initiate a card reset or power-cycle sequence. The serial interface configures which outputs are enabled and sets the fault-reporting mask.