LM5000_07 Datasheet, PDF (1/18 Pages) National Semiconductor (TI) – High Voltage Switch Mode Regulator

February 2007
LM5000
High Voltage Switch Mode Regulator
General Description
The LM5000 is a monolithic integrated circuit specifically de-
signed and optimized for flyback, boost or forward power
converter applications. The internal power switch is rated for
a maximum of 80V, with a current limit set to 2A. Protecting
the power switch are current limit and thermal shutdown cir-
cuits. The current mode control scheme provides excellent
rejection of line transients and cycle-by-cycle current limiting.
An external compensation pin and the built-in slope compen-
sation allow the user to optimize the frequency compensation.
Other distinctive features include softstart to reduce stresses
during start-up and an external shutdown pin for remote ON/
OFF control. There are two operating frequency ranges avail-
able. The LM5000-3 is pin selectable for either 300kHz (FS
Grounded) or 700kHz (FS Open). The LM5000-6 is pin se-
lectable for either 600kHz (FS Grounded) or 1.3MHz (FS
Open). The device is available in a low profile 16-lead TSSOP
package or a thermally enhanced 16-lead LLP package.
Features
■ ^{80V internal switch}
■ ^{Operating input voltage range of 3.1V to 40V}
■ ^{Pin selectable operating frequency}
300kHz/700kHz (-3)
600kHz/1.3MHz (-6)
■ ^{Adjustable output voltage}
■ ^{External compensation}
■ ^{Input undervoltage lockout}
■ ^Softstart
■ ^{Current limit}
■ ^{Over temperature protection}
■ ^{External shutdown}
■ ^{Small 16-Lead TSSOP or 16-Lead LLP package}
Applications
■ ^{Flyback Regulator}
■ ^{Forward Regulator}
■ ^{Boost Regulator}
■ ^{DSL Modems}
■ ^{Distributed Power Converters}
Typical Application Circuit
LM5000 Flyback Converter
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