LM2731_14 Datasheet, PDF (1/22 Pages) Texas Instruments – 0.6/1.6 MHz Boost Converters With 22V Internal FET Switch in SOT-23

LM2731
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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
FEATURES
1
•2 22V DMOS FET switch
• 1.6 MHz (“X”), 0.6 MHz (“Y”) switching
frequency
• Low R_DS(ON) DMOS FET
• Switch current up to 1.8A
• Wide input voltage range (2.7V–14V)
• Low shutdown current (<1 µA)
• 5-Lead SOT-23 package
• Uses tiny capacitors and inductors
• Cycle-by-cycle current limiting
• Internally compensated
APPLICATIONS
• White LED Current Source
• PDA’s and Palm-Top Computers
• Digital Cameras
• Portable Phones and Games
• Local Boost Regulator
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.
X
1.6 MHz
Table 1. Switch Frequency
Y
0.6 MHz
Typical Application Circuit
5 VIN
SHDN
GND
R3
51K
C1
2.2PF
L1/10PH
VIN ^U1 SW
LM2731 ³;´
SHDN
FB
GND
R2
13.3K
D1
MBR0520
R1/117K
CF
220pF
12V
OUT
500mA
(TYP)
C2
4.7PF
Efficiency vs Load Current
100
5 - 12V Boost
^y_ s Υ]}v
90
80
70
0 100 200 300 400 500
LOAD CURRENT (mA)
3.3 VIN
SHDN
GND
R3
51K
C1
2.2PF
L1/6.8PH
VIN ^U1 SW
LM2731 ³<´
SHDN
FB
GND
R2
13.3K
D1
MBR0520
R1/40.5K
CF
470pF
5V
OUT
700mA
(TYP)
C2
22PF
Efficiency vs Load Current
100
3.3 -5V Boost
^z_ s Υ]}v
90
80
70
0 200 400 600 800
LOAD CURRENT (mA)
1
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Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
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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.
Copyright © 2004–2010, Texas Instruments Incorporated