SM72485 Datasheet, PDF (1/16 Pages) National Semiconductor (TI) – SolarMagic 100V, 150 mA Constant On-Time Buck Switching Regulator

SM72485
May 10, 2011
SolarMagic 100V, 150 mA Constant On-Time Buck
Switching Regulator
General Description
The SM72485 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
package. The regulator is based on a control scheme using
an ON time inversely proportional to V_IN. 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 fea-
tures include: Thermal Shutdown, V_CC under-voltage lockout,
Gate drive under-voltage lockout, Max Duty Cycle limiter, and
a pre-charge switch.
■ ^{Operating frequency remains constant with varying line}
voltage and load current
■ ^{Adjustable output voltage from 2.5V}
■ ^{Highly efficient operation}
■ ^{Precision internal reference}
■ ^{Low bias current}
■ ^{Intelligent current limit}
■ ^{Thermal shutdown}
Typical Applications
■ ^{PV Panel Smart Junction Boxes}
■ ^{Non-Isolated Telecommunication Buck Regulator}
■ ^{Secondary High Voltage Post Regulator}
■ ^{+42V Automotive Systems}
Features
■ ^{Renewable Energy Grade}
■ ^{Operating input voltage range: 6V to 95V}
■ ^{Integrated 100V, N-Channel buck switch}
■ ^{Internal start-up regulator}
■ ^{No loop compensation required}
■ ^{Ultra-Fast transient response}
■ ^{On time varies inversely with input voltage}
Package
■ ^{MSOP - 8}
■ ^{LLP - 8 (4mm x 4mm)}
Typical Application, Basic Step-Down Regulator
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