LM2744 Datasheet, PDF (1/32 Pages) National Semiconductor (TI) – Low Voltage N-Channel MOSFET Synchronous Buck Regulator Controller with External Reference

LM2744
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SNVS292E – SEPTEMBER 2004 – REVISED JANUARY 2012
LM2744 Low Voltage N-Channel MOSFET Synchronous Buck Regulator Controller with
External Reference
Check for Samples: LM2744
FEATURES
1
•2 Power stage input voltage from 1V to 16V
• Control stage input voltage from 3V to 6V
• Output voltage adjustable down to 0.5V
• Power good flag and shutdown
• Output overvoltage and undervoltage
detection
• External reference voltage 0.5V to 1.5V
• Low-side adjustable current sensing
• Adjustable soft-start
• Tracking and sequencing with shutdown and
soft start pins
• Switching frequency from 50 kHz to 1 MHz
• TSSOP-14 package
APPLICATIONS
• 3.3V Buck Regulation
• Cable Modem, DSL and ADSL
• Laser Jet and Ink Jet Printers
• Low Voltage Power Modules
• DSP, ASIC, Core and I/O
• DDR Memory Termination Supply
DESCRIPTION
The LM2744 is a high-speed synchronous buck regulator controller with an externally adjustable reference
voltage (between 0.5V to 1.5V). It can provide simple down conversion to output voltages as low as 0.5V.
Though the control sections of the IC are rated for 3 to 6V, the driver sections are designed to accept input
supply rails as high as 16V. The use of adaptive non-overlapping MOSFET gate drivers helps avoid potential
shoot-through problems while maintaining high efficiency. The IC is designed for the more cost-effective option of
driving only N-channel MOSFETs in both the high-side and low-side positions. It senses the low-side switch
voltage drop for providing a simple, adjustable current limit.
The fixed-frequency voltage-mode PWM control architecture is adjustable from 50 kHz to 1 MHz with one
external resistor. This wide range of switching frequency gives the power supply designer the flexibility to make
better tradeoffs between component size, cost and efficiency.
Features include soft-start, input undervoltage lockout (UVLO) and Power Good (based on both undervoltage
and overvoltage detection). In addition, the shutdown pin of the IC can be used for providing startup delay, and
the soft-start pin can be used for implementing precise tracking, for the purpose of sequencing with respect to an
external rail.
1
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2
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
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