LM2744_15 Datasheet, PDF (1/33 Pages) Texas Instruments – Low Voltage N-Channel MOSFET Synchronous Buck Regulator Controller with External Reference

LM2744
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SNVS292F – SEPTEMBER 2004 – REVISED MARCH 2013
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
• 14-Pin TSSOP 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.
TYPICAL APPLICATION
V_CC = 3.3V
D1
C_BOOT
V_IN = 3.3V
R_CC
R_PULL-UP
C_CC
R_FADJ
C_SS
External
Reference
0.5 to 1.5V
V_CC
SD
PWGD
FREQ
LM2744
SS/TRACK
V_REF
EAO
HG
BOOT
I_SEN
LG
SGND
PGND
FB
C_C1
C_C2
R_C1
Q1
R_CS
L1
R_C2
C_C3
C_IN1,2
V_OUT = 1.2V@4A
R_FB2
+
C_O1,2
R_FB1
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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