ExpressCard power switch — 45 mOhm Rds(on) and 1.3 A per output
The TPS2231PWRG4 is a three-output high-side power switch from Texas Instruments, designed to control the 1.5 V and 3.3 V supply rails in ExpressCard slots. Each output delivers up to 1.3 A continuous, with a typical on-resistance of 45 mOhm — low enough that I²R loss at full load stays under 80 mW per channel in the TSSOP-20 package.
Fixed protection limits — no trimming
Fault protection is fixed: current limiting and over-temperature shutdown are built in, with no adjustable resistor or external sense element. The 1.3 A maximum output is the hard ceiling — if the downstream load draws more, the switch cycles into current limit. The Power Good and Status Flag outputs give the host controller a clean fault handshake.
The 20-TSSOP package (4.40 mm wide) is a standard surface-mount footprint, reflow-compatible with a typical MSL-1 moisture sensitivity level.