LM5008 Datasheet, PDF (1/15 Pages) National Semiconductor (TI) – High Voltage (100V) Step Down Switching Regulator

October 2004
LM5008
High Voltage (100V) Step Down Switching Regulator
General Description
The LM5008 Step Down Switching Regulator features all of
the functions needed to implement a low cost, efficient, Buck
bias regulator. This high voltage regulator contains an 100 V
N-Channel Buck Switch. The device is easy to implement
and is provided in the MSOP-8 and the thermally enhanced
LLP-8 packages. The regulator is based on a hysteretic
control scheme using an ON time inversely proportional to
V_IN. This feature allows the operating frequency to remain
relatively constant. The hysteretic control 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 protection while providing
minimum foldback. Other protection features include: Ther-
mal Shutdown, V_CC under-voltage lockout, Gate drive under-
voltage lockout, and Max Duty Cycle limiter
Features
n Integrated 100V, N-Channel buck switch
n Internal V_CC regulator
n No loop compensation required
n Ultra-Fast transient response
n On time varies inversely with line voltage
n Operating frequency remains constant with varying line
voltage and load current
n Adjustable output voltage
n Highly efficient operation
n Precision internal reference
n Low bias current
n Intelligent current limit protection
n Thermal shutdown
Typical Applications
n Non-Isolated Telecommunication Buck Regulator
n Secondary High Voltage Post Regulator
n +42V Automotive Systems
Package
n MSOP - 8
n LLP - 8 (4mm x 4mm)
Connection Diagram
Ordering Information
Order Number
LM5008MM
LM5008SD
Package Type
MSOP-8
LLP-8
20097902
8-Lead MSOP, LLP
NSC Package Drawing
MUA08A
SDC08A
Supplied As
1000 Units on Tape and Reel
1000 Units on Tape and Reel
© 2004 National Semiconductor Corporation DS200979
www.national.com