1 Features

1• Operating Input Voltage Range: 6 V to 95 V

• Integrated 100-V N-Channel Buck Switch

• Internal Start-Up Regulator

• No Loop Compensation Required

• Ultra-Fast Transient Response

• On-Time Varies Inversely With Input Voltage

• Operating Frequency Remains Constant With

Varying Line Voltage and Load Current

• Adjustable Output Voltage From 2.5 V

• Highly Efficient Operation

• Precision Internal Reference

• Low Bias Current

• Intelligent Current Limit

• Thermal Shutdown

• 8-Pin VSSOP and 8-Pin WSON Packages

• Create a Custom Design Using the LM5008A With

the WEBENCH® Power Designer

2 Applications

• Non-Isolated Telecommunication Buck Regulators

• Secondary High-Voltage Post Regulators

• 48-V Automotive Systems

3 Description

The LM5008A DC/DC converter is a functional variant

of the LM5008 COT Buck Switching Regulator. The

functional differences of the LM5008A are: the

minimum input operating voltage is 6 V, the on-time

equation is slightly different, and the requirement for

a minimum load current is removed.

The LM5008A 350-mA step-down switching regulator

features all of the functions required to implement a

low-cost and efficient buck regulator. This highvoltage

converter has an integrated 100-V N-channel

buck switch and operates over an input voltage range

of 6 V to 95 V. The device is easy to implement and

is provided in 8-pin VSSOP and the thermally

enhanced 8-pin WSON packages. The converter

uses PWM control scheme with an on-time inversely

proportional to VIN. This feature allows the operating

frequency to remain relatively constant. The control

scheme requires no loop compensation. An intelligent

current limit is implemented with forced off-time,

which is inversely proportional to VOUT. This scheme

ensures short-circuit control while providing minimum

foldback. Other features include: thermal shutdown,

VCC undervoltage lockout, gate drive undervoltage

lockout, maximum duty cycle limiter, and a precharge

switch.