DC-DC Regulator. LM2734 Datasheet


LM2734 Regulator. Datasheet pdf. Equivalent


LM2734


Thin SOT23 1A Load Step-Down DC-DC Regulator
LM2734 Thin SOT23 1A Load Step-Down DC-DC Regulator

October 2004

LM2734 Thin SOT23 1A Load Step-Down DC-DC Regulator
General Description
The LM2734 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 regulation in the smallest possible PCB area. With a minimum of external components and online design support through WEBENCH™, the LM2734 is easy to use. The ability to drive 1A loads with an internal 300mΩ NMOS switch using state-of-the-art 0.5µm BiCMOS technology 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 20V input operating range down to the minimum output voltage of 0.8V. Switching frequency is internally set to 550kHz (LM2734Y) or 1.6MHz (LM2734X), 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 LM2734 utilizes current-mode control and internal compensation to provide high-performance regulation over a wide range of operating conditions. Additional featur...



LM2734
October 2004
LM2734
Thin SOT23 1A Load Step-Down DC-DC Regulator
General Description
The LM2734 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 LM2734 is easy to use.
The ability to drive 1A loads with an internal 300mNMOS
switch using state-of-the-art 0.5µm BiCMOS technology re-
sults 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 20V input operating range down to the minimum
output voltage of 0.8V. Switching frequency is internally set
to 550kHz (LM2734Y) or 1.6MHz (LM2734X), 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 LM2734 utilizes current-mode control and in-
ternal compensation to provide high-performance regulation
over a wide range of operating conditions. Additional fea-
tures include internal soft-start circuitry to reduce inrush
current, pulse-by-pulse current limit, thermal shutdown, and
output over-voltage protection.
Features
n Thin SOT23-6 package
n 3.0V to 20V input voltage range
n 0.8V to 18V output voltage range
n 1A output current
n 550kHz (LM2734Y) and 1.6MHz (LM2734X)
switching frequencies
n 300mNMOS switch
n 30nA shutdown current
n 0.8V, 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
VIN = 5V, VOUT = 3.3V
20102301
WEBENCHis a trademark of Transim.
© 2004 National Semiconductor Corporation DS201023
20102345
www.national.com

LM2734
Connection Diagram
20102305
6-Lead TSOT
NS Package Number MK06A
Ordering Information
Order Number Package Type NSC Package Drawing
LM2734XMK
LM2734YMK
LM2734XMKX
TSOT-6
MK06A
LM2734YMKX
* Contact the local sales office for the lead-free package.
Package Marking
SFDB
SFEB
SFDB
SFEB
Supplied As
1000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
3000 Units on Tape and Reel
Pin Description
Pin Name
Function
1
BOOST
Boost voltage that drives the internal NMOS control switch. A
bootstrap capacitor is connected between the BOOST and SW
pins.
2
GND
Signal and Power ground pin. Place the bottom resistor of the
feedback network as close as possible to this pin for accurate
regulation.
3 FB Feedback pin. Connect FB to the external resistor divider to set
output voltage.
4 EN Enable control input. Logic high enables operation. Do not allow
this pin to float or be greater than VIN + 0.3V.
5 VIN Input supply voltage. Connect a bypass capacitor to this pin.
6 SW Output switch. Connects to the inductor, catch diode, and
bootstrap capacitor.
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