FEATURES
s
s
s
s
s
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 V
OUT
< 2.6V
should use the LTC3423.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Burst Mode and OPTI-LOOP are registered trademarks of Linear Technology Corporation.
s
s
s
s
s
s
s
s
s
s
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 (V
OUT
< 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 MSOP Package
APPLICATIO S
s
s
s
s
s
s
s
Pagers
Handheld Instruments
Cordless Phones
Wireless Handsets
GPS Receivers
Battery Backup
CCFL Backlights
TYPICAL APPLICATION
All-Ceramic-Capacitor 2-Cell to 3.3V at 500mA Step-Up Converter
V
IN
= 1.8V to 3V
L1
4.7µH
V
OUT
3.3V
500mA
SW
V
OUT
4
7
8
9
5
C3
470pF
R5
82k
C4
4.7pF
R1
549k
EFFICIENCY (%)
100
3
10
LTC3401
V
IN
SHDN
R2
909k
Burst Mode
90 OPERATION
80
70
1MHz
FIXED
FREQUENCY
+
2
CELLS
2
6
MODE/SYNC FB
PGOOD
R
t
V
C
GND
C2
22µF
60
50
40
30
20
10
0
C1
4.7µF
1
R
t
30.1k
V
IN
= 2.4V WITH SCHOTTKY
0.1
1
10
I
OUT
(mA)
100
1000
3401 TA02
0 = FIXED FREQUENCY
1 = Burst Mode OPERATION
C1: TAIYO YUDEN JMK212BJ475MG
C2: TAIYO YUDEN JMK325BJ226MM
L1: SUMIDA CD43-4R7M
3404 TA01
U
U
U
Efficiency
3401fa
1
LINER [ LINEAR TECHNOLOGY ]
