1 Features
• Newer product: LM5163 100-V, 0.5-A synchronous
buck DC/DC converter
• Integrated N-channel MOSFET
• 150-mA output current capability
• Ultra-fast transient response
• No loop compensation required
• VIN feedforward provides constant operating
frequency
• Switching frequency can exceed 600 kHz
• Highly efficient operation
• 2% accurate 2.5-V feedback from
–40°C to +125°C
• Internal start-up regulator
• Intelligent current limit protection
• External shutdown control
• Thermal shutdown
• 8-pin VSSOP and thermally enhanced 8-pin
WSON packages

2 Applications
• Heat sink eliminator for classic linear regulator
applications
• 12-V, 24-V, 36-V, and 48-V rectified AC systems
• Non-isolated AC mains charge-coupled supplies
• LED current source

3 Description
The LM5009 step-down switching regulator features
all of the functions needed to implement a low-cost
and efficient, buck regulator. This device is capable
of driving a 150-mA load current from a 9.5-V to 95-
V input source. The switching frequency can exceed
600 kHz, depending on the input and output voltages.
The output voltage can be set from 2.5 V to 85 V. This
high-voltage regulator contains an N-channel buck
switch and an internal startup regulator. The device is
easy to implement and is provided in 8-pin VSSOP
and thermally-enhanced, 8-pin WSON packages.
The regulator operation is based on a control
scheme using an on-time inversely proportional to
VIN. This feature allows the operating frequency
to remain relatively constant over load and input
voltage variations. The control scheme requires no
loop compensation, resulting in an ultrafast transient
response. An intelligent current limit is implemented
with forced off-time that is inversely proportional to
VOUT. This scheme ensures short-circuit protection
and provides minimum foldback. Other features
include thermal shutdown, VCC undervoltage lockout,
gate drive undervoltage lockout, and maximum duty
cycle limiter.
The new product LM5163 offers reduced BOM count,
reduced solution size, lower operating quiescent
current and many other features. Start WEBENCH®
design with LM5163.