LM2743 Datasheet, PDF (1/23 Pages) National Semiconductor (TI) – N-Channel FET Synchronous Buck Regulator Controller for Conversion from 3.3V

February 2005
LM2743
Low Voltage N-Channel MOSFET Synchronous Buck
Regulator Controller
General Description
The LM2743 is a high-speed synchronous buck regulator
controller with an accurate feedback voltage accuracy of
±2%. It can provide simple down conversion to output volt-
ages as low as 0.6V. 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 resis-
tor. This wide range of switching frequency gives the power
supply designer the flexibility to make better tradeoffs be-
tween 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.
Features
n Power stage input voltage from 1V to 16V
n Control stage input voltage from 3V to 6V
n Output voltage adjustable down to 0.6V
n Power good flag and shutdown
n Output overvoltage and undervoltage detection
n ±2% feedback voltage accuracy over temperature
n Low-side adjustable current sensing
n Adjustable soft-start
n Tracking and sequencing with shutdown and soft start
pins
n Switching frequency from 50 kHz to 1 MHz
n TSSOP-14 package
Applications
n 3.3V Buck Regulation
n Cable Modem, DSL and ADSL
n Laser Jet and Ink Jet Printers
n Low Voltage Power Modules
n DSP, ASIC, Core and I/O
Typical Application
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