PCMCIA slot power switch — 4 outputs, 95 mOhm, industrial temp
The Texas Instruments TPS2224ADB is a PCMCIA power-distribution switch designed to manage the 3.3 V, 5 V, and 12 V supply rails in a PC Card or CardBus slot. It integrates four high-side outputs with a 3:4 input-to-output ratio, meaning three supply inputs are selectively routed to four output channels — the typical configuration for a dual-slot PCMCIA controller where each slot needs VCC and VPP rails.
Fault protection and status reporting
Fixed current limiting and over-temperature shutdown are built in — no external sense resistor or comparator needed. The Status Flag output (open-drain, active low) asserts when a fault condition is detected, which a host controller or PCMCIA bridge can poll to manage slot power-down sequencing. The serial interface controls output enable and VCC/VPP selection, reducing the GPIO count required from the host. Because Vcc/Vdd is not required for the switch's internal logic, the device powers up from the load supply rails directly — a detail that simplifies the power-up sequence in a multi-rail system.