LM5009 Datasheet, PDF (1/14 Pages) National Semiconductor (TI) – 150 mA, 100V Step-Down Switching Regulator

February 2006
LM5009
150 mA, 100V Step-Down Switching Regulator
General Description
The LM5009 Step Down Switching Regulator features all of
the functions needed to implement a low cost, efficient, Buck
bias regulator. This device is capable of driving a 150 mA
load current from a 9.5V to 95V input source. The switching
frequency can exceed 600 kHz, depending on the input and
output voltages. The output voltage may be set from 2.5V to
85V. This high voltage regulator contains an N-Channel buck
switch and internal startup regulator. The device is easy to
implement and is provided in the MSOP-8 and the thermally
enhanced LLP-8 packages. The LM5009 is a well suited
alternative to a high voltage monolithic or discrete linear
solution where the power loss becomes unacceptable. The
regulator’s operation is based on a hysteretic 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 hyster-
etic control requires no loop compensation, resulting in an
ultra-fast transient response. An intelligent current limit is
implemented with forced OFF time, which is inversely pro-
portional to Vout. This scheme ensures short circuit protec-
tion while providing minimum foldback. Other features in-
clude: Thermal Shutdown, Vcc under-voltage lockout, Gate
drive under-voltage lockout, and Maximum Duty Cycle lim-
iter.
Features
n Integrated N-Channel MOSFET
n Guaranteed 150 mA output current capability
n Ultra-Fast Transient Response
n No loop compensation required
n Vin feed forward provides constant operating frequency
n Switching frequency can exceed 600 kHz
n Highly efficient operation
n 2% accurate 2.5V feedback from -40˚C to 125˚C
n Internal startup regulator
n Intelligent current limit protection
n External shutdown control
n Thermal shutdown
n MSOP-8 and thermally enhanced LLP packages
Typical Applications
n Heat sink eliminator for classic linear regulator
applications
n 12V, 24V, 36V, and 48V rectified AC systems
n 42V Automotive
n Non-isolated AC mains charge coupled supplies
n LED Current Source
Package
n MSOP - 8
n LLP - 8 (4mm x 4mm) (Available Soon)
Typical Application Circuit
Basic Stepdown Regulator
© 2006 National Semiconductor Corporation DS201658
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