LTC3400/LTC3400B
600mA, 1.2MHz Micropower
Synchronous Boost Converter
in ThinSOT
FEATURES
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DESCRIPTIO
Up to 92% Efficiency
Generates 3.3V at 100mA from a Single AA Cell
Low Start-Up Voltage: 0.85V
1.2MHz Fixed Frequency Switching
Internal Synchronous Rectifier
2.5V to 5V Output Range
Automatic Burst Mode
®
Operation (LTC3400)
Continuous Switching at Light Loads (LTC3400B)
Logic Controlled Shutdown (< 1µA)
Antiringing Control Minimizes EMI
Tiny External Components
Low Profile (1mm) SOT-23 Package
The LTC
®
3400/LTC3400B are synchronous, fixed fre-
quency, step-up DC/DC converters delivering high effi-
ciency in a 6-lead ThinSOT™ package. Capable of supplying
3.3V at 100mA from a single AA cell input, the devices
contain an internal NMOS switch and PMOS synchronous
rectifier.
A switching frequency of 1.2MHz minimizes solution
footprint by allowing the use of tiny, low profile inductors
and ceramic capacitors. The current mode PWM design is
internally compensated, reducing external parts count.
The LTC3400 features automatic shifting to power saving
Burst Mode operation at light loads, while the LTC3400B
features continuous switching at light loads. Antiringing
control circuitry reduces EMI concerns by damping the
inductor in discontinuous mode, and the devices feature
low shutdown current of under 1µA.
Both devices are available in the low profile (1mm)
SOT-23 package.
, LTC, LT and Burst Mode are registered trademarks of Linear Technology Corporation.
ThinSOT is a trademark of Linear Technology Corporation.
APPLICATIO S
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Pagers
MP3 Players
Digital Cameras
LCD Bias Supplies
Handheld Instruments
Wireless Handsets
GPS Receivers
TYPICAL APPLICATIO
L1
4.7µH
100
+
SINGLE
AA CELL
C1
4.7µF
1
6
SW
V
IN
V
OUT
5
R1
1.02M
1%
R2
604k
1%
V
OUT
3.3V
100mA
C2
4.7µF
90
EFFICIENCY (%)
80
70
60
50
FIGURE 1 CIRCUIT
WITH OPTIONAL SCHOTTKY DIODE
(SEE APPLICATIONS INFORMATION)
1
10
100
LOAD CURRENT (mA)
1000
3400 F01a
LTC3400
OFF ON
4
SHDN
GND
2
C1, C2: TAIYO-YUDEN X5R EMK316BJ475ML
L1: COILCRAFT DO160C-472
FB
3
3400 F01
40
0.1
Figure 1. Single Cell to 3.3V Synchronous Boost Converter
U
Efficiency
V
IN
= 2.4V
V
IN
= 1.5V
3400fa
U
U
1
LINER [ LINEAR TECHNOLOGY ]
