Datasheet
LTC3400/LTC3400B
1
3400fa
■
Pagers
■
MP3 Players
■
Digital Cameras
■
LCD Bias Supplies
■
Handheld Instruments
■
Wireless Handsets
■
GPS Receivers
■
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
600mA, 1.2MHz Micropower
Synchronous Boost Converter
in ThinSOT
Figure 1. Single Cell to 3.3V Synchronous Boost Converter
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.
ThinSOT is a trademark of Linear Technology Corporation.
SW
L1
4.7µH
V
OUT
LTC3400
FB
V
IN
SHDN
2
1
3
3400 F01
R1
1.02M
1%
C1, C2: TAIYO-YUDEN X5R EMK316BJ475ML
L1: COILCRAFT DO160C-472
R2
604k
1%
C2
4.7µF
C1
4.7µF
SINGLE
AA CELL
V
OUT
3.3V
100mA
5
4
6
GND
+
OFF
ON
LOAD CURRENT (mA)
60
EFFICIENCY (%)
80
100
50
70
90
0.1 10 100 1000
3400 F01a
40
1
V
IN
= 2.4V
V
IN
= 1.5V
FIGURE 1 CIRCUIT
WITH OPTIONAL SCHOTTKY DIODE
(SEE APPLICATIONS INFORMATION)
Efficiency
FEATURES
DESCRIPTIO
U
APPLICATIO S
U
TYPICAL APPLICATIO
U
, LTC, LT and Burst Mode are registered trademarks of Linear Technology Corporation.