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.