High-side P-channel power switch with fault protection
The MAX891LEUA+: The built-in fault protection includes adjustable current limiting and over-temperature shutdown, which means the switch can handle a shorted output or a thermal runaway condition without cascading upstream.
On-resistance and thermal envelope
Typical Rds on is 120 mOhm, so at 500 mA the conduction loss is about 30 mW — negligible for most loads, but the 8-uMAX package's thermal impedance should be checked if the part runs near the 85 °C ambient limit.
Control and status interface
The On/Off interface is non-inverting, so a logic high on the enable pin turns the output on; the Status Flag output asserts low when the switch is in current limit or thermal shutdown. No external Vcc supply is required — the gate drive is derived from the load voltage, which simplifies the BOM for a single-rail system.
Package and board integration
The MAX891LEUA+ is offered in an 8-uMAX/uSOP (3.00 mm width) surface-mount package, supplied in tube format. The narrow 0.118-inch pitch lands on a standard MSOP-8 footprint.