LM2736 Datasheet, PDF (1/22 Pages) National Semiconductor (TI) – Thin SOT23 750mA Load Step-Down DC-DC Regulator

October 2004
LM2736
Thin SOT23 750mA Load Step-Down DC-DC Regulator
General Description
The LM2736 regulator is a monolithic, high frequency, PWM
step-down DC/DC converter in a 6-pin Thin SOT23 package.
It provides all the active functions to provide local DC/DC
conversion with fast transient response and accurate regu-
lation in the smallest possible PCB area.
With a minimum of external components and online design
support through WEBENCH™, the LM2736 is easy to use.
The ability to drive 750mA loads with an internal 350mΩ
NMOS switch using state-of-the-art 0.5µm BiCMOS technol-
ogy results in the best power density available. The world
class control circuitry allows for on-times as low as 13ns,
thus supporting exceptionally high frequency conversion
over the entire 3V to 18V input operating range down to the
minimum output voltage of 1.25V. Switching frequency is
internally set to 550kHz (LM2736Y) or 1.6MHz (LM2736X),
allowing the use of extremely small surface mount inductors
and chip capacitors. Even though the operating frequencies
are very high, efficiencies up to 90% are easy to achieve.
External shutdown is included, featuring an ultra-low
stand-by current of 30nA. The LM2736 utilizes current-mode
control and internal compensation to provide high-
performance regulation over a wide range of operating con-
ditions. Additional features include internal soft-start circuitry
to reduce inrush current, pulse-by-pulse current limit, ther-
mal shutdown, and output over-voltage protection.
Features
n Thin SOT23-6 package
n 3.0V to 18V input voltage range
n 1.25V to 16V output voltage range
n 750mA output current
n 550kHz (LM2736Y) and 1.6MHz (LM2736X)
switching frequencies
n 350mΩ NMOS switch
n 30nA shutdown current
n 1.25V, 2% internal voltage reference
n Internal soft-start
n Current-Mode, PWM operation
n WEBENCH online design tool
Applications
n Local Point of Load Regulation
n Core Power in HDDs
n Set-Top Boxes
n Battery Powered Devices
n USB Powered Devices
n DSL Modems
n Notebook Computers
Typical Application Circuit
Efficiency vs Load Current "X"
V_IN = 5V, V_OUT = 3.3V
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