LM3311_07 Datasheet, PDF (1/32 Pages) National Semiconductor (TI) – Step-Up PWM DC/DC Converter with Integrated LDO, Op-Amp, and Gate Pulse Modulation Switch

November 26, 2007
LM3311
Step-Up PWM DC/DC Converter with Integrated LDO, Op-
Amp, and Gate Pulse Modulation Switch
General Description
The LM3311 is a step-up DC/DC converter integrated with an
LDO, an Operational Amplifier, and a gate pulse modulation
switch. The boost (step-up) converter is used to generate an
adjustable output voltage and features a low R_DSON internal
switch for maximum efficiency. The operating frequency is
selectable between 660kHz and 1.28MHz allowing for the use
of small external components. An external soft-start pin en-
ables the user to tailor the soft-start time to a specific appli-
cation and limit the inrush current. The LDO also has an
adjustable output voltage and is stable using ceramic output
capacitors. The Op-Amp is capable of sourcing/sinking 135-
mA of current (typical) for the standard version and 200mA
(typical) for the HIOP version. The gate pulse modulation
switch can operate with a VGH voltage of 5V to 30V. The
LM3311 is available in a low profile 24-lead LLP package.
Features
■ ^{Boost converter with a 2A, 0.18Ω switch}
■ ^{Boost output voltage adjustable up to 20V}
■ ^{Operating voltage range of 2.5V to 7V}
■ ^{660kHz/1.28MHz pin selectable switching frequency}
■ ^{Adjustable soft-start function}
■ ^{Input undervoltage protection}
■ ^{Over temperature protection}
■ ^{Adjustable low dropout linear regulator (LDO)}
■ ^{Integrated Op-Amp}
■ ^{Integrated gate pulse modulation (GPM) switch}
■ ^{24-Lead LLP package}
Applications
■ ^{TFT Bias Supplies}
■ ^{Portable Applications}
Typical Application Circuit
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