Efficiency vs Load Current

LOAD CURRENT (mA)

3.3 -5V Boost

^z_ s Υ]}v

0

200

400

600

800

70

80

90

100

LM2731

³<´

SW

FB

GND

SHDN

U1

R3

51K

SHDN

GND

C1

2.2PF

R2

13.3K

CF

470pF

D1

MBR0520

R1/40.5K

L1/6.8PH

C2

22PF

5V

OUT

700mA

(TYP)

Efficiency vs Load Current

LOAD CURRENT (mA)

0 100

200

300 400

70

80

90

100

LM2731

³;´

SW

FB

GND

SHDN

U1

R3

51K

SHDN

GND

C1

2.2PF

R2

13.3K

CF

220pF

D1

MBR0520

R1/117K

L1/10PH

C2

4.7PF

12V

OUT

500mA

(TYP)

500

5 - 12V Boost

^y_ s Υ]}v

LM2731

www.ti.com

SNVS217E – MAY 2004 – REVISED APRIL 2010

LM2731 0.6/1.6 MHz Boost Converters With 22V Internal FET Switch in SOT-23

Check for Samples: LM2731

1

FEATURES

•

Cycle-by-cycle current limiting

•

Internally compensated

2

•

22V DMOS FET switch

•

1.6 MHz (“X”), 0.6 MHz (“Y”) switching

APPLICATIONS

frequency

•

White LED Current Source

•

•

PDA’s and Palm-Top Computers

•

Switch current up to 1.8A

•

Digital Cameras

•

Wide input voltage range (2.7V–14V)

•

Portable Phones and Games

•

Low shutdown current (<1 µA)

•

Local Boost Regulator

•

5-Lead SOT-23 package

•

Uses tiny capacitors and inductors

DESCRIPTION

The LM2731 switching regulators are current-mode boost converters operating at fixed frequencies of 1.6 MHz

(“X” option) and 600 kHz (“Y” option).

The use of SOT-23 package, made possible by the minimal power loss of the internal 1.8A switch, and use of

small inductors and capacitors result in the industry's highest power density. The 22V internal switch makes

these solutions perfect for boosting to voltages up to 20V.

These parts have a logic-level shutdown pin that can be used to reduce quiescent current and extend battery life.

Protection is provided through cycle-by-cycle current limiting and thermal shutdown. Internal compensation

simplifies design and reduces component count.

Table 1. Switch Frequency

X

Y

1.6 MHz

0.6 MHz

Typical Application Circuit

1

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

2

All trademarks are the property of their respective owners.

PRODUCTION DATA information is current as of publication date.

Copyright © 2004–2010, Texas Instruments Incorporated

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.