LM3544 Datasheet PDF | National Semiconductor

National Semiconductor LM3544

The LM3544 is a quad high-side power switch that is an excellent choice for use in Root, Self-Powered and BusPowered USB (Universal Serial Bus) Hubs. The LM3544 accepts input voltages between 2.7V and 5.5V. The Enable logic inputs, available in active-high and activelow versions, can be powered off any voltage in the 2.7V to 5.5V range.

Part No.	LM3544
Datasheet	LM3544 Download
Manufacturer	National Semiconductor
Description	Quad Port USB Power Distribution Switch and Over-Current Protection
Buy	Stock & Price

GENERAL DESCRIPTION

Independent port enables, flag signals to alert USB controllers of error conditions, controlled start-up in hot-plug events, and short circuit protection all satisfy USB requirements. The LM3544 limits the continuous current through a single port to 1.25A (max.) when it is shorted to ground. The low on-state resistance of the LM3544 switches ensures the LM3544 will satisfy USB voltage drop requirements, even when current through a switch reaches 500 mA. Thus, High-Powered USB Functions, Low-Powered USB functions, and Bus-Powered USB Hubs can all be powered off a Root or Self-Powered USB Hub containing the LM3544. Added features of the LM3544 include current foldback to reduce power consumption in current overload conditions, thermal shutdown to prevent device failure caused by highcurrent overheating, and undervoltage lockout to keep switches from operating if the input voltage is below acceptable levels.

FEATURES

n Compatible with USB1.1 and USB 2.0 n 90mΩ (typ.) H...