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.