LM3525 Single Port USB Power Switch and Over-Current Protection
January 2000
LM3525
Single Port USB Power Switch and Over-Current
Protection
General Description
The LM3525 provides Universal Serial Bus standard power
switch and over-current protection for all host port applica-
tions. The single port device is ideal for Notebook PC and
Handheld PC applications that supply power to one port.
A 1 ms delay on fault flag output prevents erroneous over-
current reporting caused by inrush currents during the
hot-plug events.
The LM3525 accepts an input voltage between 2.7V and
5.5V allowing use as a device-based inrush current limiter
for 3.3V USB peripherals, as well as Root and Self-Powered
Hubs at 5.5V. The Enable input accepts both 3.3V and 5.0V
logic thresholds.
The small size, low R
ON
, and 1 ms fault flag delay make the
LM3525 a good choice for root hubs as well as ganged
power control in space-critical self-powered hubs.
Features
n
1 ms Fault Flag Delay During Hot-Plug Events
n
Smooth Turn-On Eliminates Inrush Induced Voltage
Drop
n
UL Recognized Component: REF
#
205202
n
1A Nominal Short Circuit Output Current Protects
Notebook PC Power Supplies
n
Thermal Shutdown Protects Device in Direct Short
Condition
n
500mA Minimum Continuous Load Current
n
Small SO-8 Package Minimizes Board Space
n
2.7V to 5.5V Input Voltage Range
n
Switch Resistance
≤
120 mΩ Max. at V
IN
= 5V
n
1µA Max Standby Current
n
100 µA Max Operating Current
n
Undervoltage 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 Inrush Limiting
n
General Purpose High Side Switch Applications
Typical Operating Circuit and Connection Diagram
DS101055-2
LM3525M-L
DS101055-1
DS101055-31
DS101055-30
LM3525M-H
© 2000 National Semiconductor Corporation
DS101055
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