High-side switch with a protection set that covers most rail faults
The TPS2553DDBVR is a single-channel, high-side N-channel power distribution switch from Texas Instruments, rated for a continuous output of 1.5 A with a typical on-resistance of 85 mOhm. It integrates adjustable current limiting, over-temperature shutdown, and undervoltage lockout (UVLO) — a protection suite that handles the common fault conditions on a 2.7 V to 6.5 V load rail without external clamp diodes or a separate supply voltage (Vcc/Vdd not required).
85 mOhm Rds(on) — what it costs in the thermal budget
At 1.5 A the 85 mOhm typical channel resistance dissipates about 190 mW. In the SOT-23-6 package, that heat has to flow through a small copper pad — the junction-to-ambient thermal resistance is high enough that the 1.5 A max is thermally constrained, not current-limited. For continuous loads above 1 A, the board layout (copper pour area under the switch) directly sets the real-world derating.
Adjustable current limit — one resistor sets the trip point
A single resistor from the ILIM pin to ground programs the overcurrent threshold. This means one BOM line can serve multiple rail budgets (e.g., 500 mA for a sensor rail, 1.2 A for a logic rail) by changing only the resistor value. The slew-rate control on the output prevents inrush from triggering a false limit on capacitive loads.
150°C junction rating — under-hood and industrial ambient
The UVLO ensures the switch stays off until the input rail is stable, which avoids partial-power glitches on the load during startup.