LM3526 Datasheet | National Semiconductor

Description The LM3526 provides Universal Serial Bus standard power switch and over-current protection for all host port applications. The dual port device is ideal for Notebook and desktop PC’s that supply power to more than one port. A 1 ms delay on the fault flag output prevents erroneous overcurrent reporting caused by in-rush currents during hot-plug events. The dual stage thermal protection circuit in the LM3526 provides individual protection to each switch and the entire device. In a short-circuit/over-current event, the switch dissipating excessive heat is turned off, allowing the second switch to continue to function uninterrupted. The LM3526 accepts an input voltage between 2.7V and 5.5V allowing use as a device-based in-rush current limiter for 3.3V USB peripherals, as well as Root and Self-Powered Hubs at 5.5V. The Enable inputs accept both 3.3V and 5.0V logic thresholds. The small size, low RON, and 1 ms fault flag delay make the LM3526 a good choice for root hubs as well as per-port power control in embedded and stand-alone hubs. Features n n n n n n n n n n n n 1 ms fault flag delay filters Hot-Plug events Smooth turn-on eliminates in-rush induced voltage drop UL recognized ponent: REF# 205202 1A nominal short circuit output current protects PC power supplies Thermal shutdown protects device in direct short condition 500m A minimum continuous load current Small SO-8 package minimizes board space 2.7V to 5.5V input voltage range 140 mΩ Max. switch resistance 1 µA Max. standby current 200 µA Max. operating current Under-voltage lockout (UVLO) Applications n Universal Serial Bus (USB) Root Hubs including Desktop and Notebook PC n USB Monitor Hubs n Other Self-Powered USB Hub Devices n High Power USB Devices Requiring In-rush Limiting n General Purpose High Side Switch Applications Typical Operating Circuit and Connection Diagram DS101097-2 LM3526-H DS101097-1 DS101097-40 DS101097-28 LM3526-L © 2000 National Semiconductor Corporation DS101097...