The uP7501 is a switch controller specifically designed to provide 5VDUAL voltage for modern motherboards. It controls the switches to power 5VDUAL plane according to the Sleeping State complaint with ACPI specification: switching in the ATX/BTX 5VCC output through an NMOS transistor in active states, or switching in the ATX/BTX 5VSB through a PMOS transistor in S3 sleep state. A MODE pin programs whether 5VDUAL is shut down or stays on during S4/S5 state.
Soft start function is implemented to limit inrush current from 5VSB supply voltage.
This part comes to a tiny SOT23-8 package.