LTC3401 データシートの表示（PDF） - Linear Technology
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LTC3401 Datasheet PDF : 16 Pages
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FEATURES
■ Synchronous Rectification: Up to 97% Efficiency
■ 1A Switch Current Rating
■ Fixed Frequency Operation Up to 3MHz
■ Wide Input Range: 0.5V to 5.5V (Operating)
■ Very Low Quiescent Current: 38μA (Burst Mode®
Operation)
■ 2.6V to 5.5V Adjustable Output Voltage
■ 0.85V (Typ) Start-Up Voltage
■ No External Schottky Diode Required (VOUT < 4.3V)
■ Synchronizable Switching Frequency
■ Burst Mode Enable Control
■ Antiringing Control Reduces Switching Noise
■ PGOOD Output
■ OPTI-LOOP® Compensation
■ Very Low Shutdown Current: < 1μA
■ Small 10-Pin MSUOP Package
APPLICATIO S
■ Pagers
■ Handheld Instruments
■ Cordless Phones
■ Wireless Handsets
■ GPS Receivers
■ Battery Backup
■ CCFL Backlights
LTC3401
1A, 3MHz Micropower
Synchronous Boost Converter
DESCRIPTIO
The LTC®3401 is a high efficiency, fixed frequency, step-
up DC/DC converter that operates from an input voltage
below 1V. The device includes a 0.16Ω N-channel MOSFET
switch and a 0.18Ω P-channel synchronous rectifier.
Switching frequencies up to 3MHz are programmed with
an external timing resistor and the oscillator can be
synchronized to an external clock. An external Schottky
diode is optional but will slightly improve efficiency.
Quiescent current is only 38μA in Burst Mode operation,
maximizing battery life in portable applications. Burst
Mode operation is user controlled and can be enabled by
driving the MODE/SYNC pin high. If the MODE/SYNC pin
has either a clock or is driven low, then fixed frequency
switching is enabled.
Other features include 1μA shutdown, antiringing control,
open-drain power good output, thermal shutdown and
current limit. The LTC3401 is available in the 10-lead
thermally enhanced MSOP package. Higher current appli-
cations should use the 2A rated LTC3402 synchronous
boost converter. Applications that require VOUT < 2.6V
should use the LTC3423.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
Burst Mode and OPTI-LOOP are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATION
All-Ceramic-Capacitor 2-Cell to 3.3V at 500mA Step-Up Converter
VIN = 1.8V to 3V
L1
4.7μH
VOUT
3.3V
500mA
+
2
CELLS
C1
4.7μF
LTC3401
3
4
VIN
SW
10
SHDN
7
VOUT
2
MODE/SYNC
FB
8
6
PGOOD
1
Rt
9
VC
GND 5
Rt
30.1k
R2
909k
C3
470pF
R5
82k
C4
R1
4.7pF 549k
C2
22μF
0 = FIXED FREQUENCY
1 = Burst Mode OPERATION
C1: TAIYO YUDEN JMK212BJ475MG
C2: TAIYO YUDEN JMK325BJ226MM
L1: SUMIDA CD43-4R7M
3404 TA01
Efficiency
100
Burst Mode
90 OPERATION
80
70
60
1MHz
FIXED
FREQUENCY
50
40
30
20
10
VIN = 2.4V WITH SCHOTTKY
0
0.1
1
10
100
IOUT (mA)
1000
3401 TA02
3401fb
1
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