LINEAR TECHNOLOGY LTC3440 User's Manual
Summary
This highly efficient Buck-Boost DC/DC converter is ideal for portable electronics like MP3 players and digital cameras, providing reliable power conversion from wide-ranging battery voltages to a stable output. The comprehensive manual details the device's advanced capabilities, including single-inductor operation, programmable high switching frequencies (up to 2MHz), and energy-saving Burst Mode functionality. It is designed for engineers building sophisticated battery-powered instruments requiring maximum efficiency and extended operational longevity.
Page 1 Text Content
LTC3440
Micropower Synchronous Buck-Boost DC/DC Converter
FEATURES DESCRIPTIO
Single Inductor The LTC®3440 is a high efficiency, fixed frequency, Buck- Fixed Frequency Operation with Battery Voltages Boost DC/DC converter that operates from input voltages Above, Below or Equal to the Output above, below or equal to the output voltage. The topology Synchronous Rectification: Up to 96% Efficiency incorporated in the IC provides a continuous transfer 25µA Quiescent Current in Burst Mode® Operation function through all operating modes, making the product Up to 600m A Continuous Output Current ideal for single lithium-ion, multicell alkaline or Ni MH No Schottky Diodes Required (VOUT < 4.3V) applications where the output voltage is within the battery VOUT Disconnected from VIN During Shutdown voltage range.
2.5V to 5.5V Input and Output Range
The device includes two 0.19Ω N-channel MOSFET
Programmable Oscillator Frequency
switches and two 0.22Ω P-channel switches. Switching
from 300k Hz to 2MHz
frequencies up to 2MHz are programmed with an external
Synchronizable Oscillator
resistor and the oscillator can be synchronized to an
Burst Mode Enable Control
external clock. Quiescent current is only 25µA in Burst
<1µA Shutdown Current
Mode operation, maximizing battery life in portable appli-
EF FI CI EN CY
Small Thermally Enhanced 10-Pin MSOP and
cations. Burst Mode operation is user controlled and can
(3mm × 3mm) DFN Packages
be enabled by driving the MODE/SYNC pin high. If the MODE/SYNC pin has either a clock or is driven low, then
APPLICATIO S
fixed frequency switching is enabled.
Palmtop Computers
Other features include a 1µA shutdown, soft-start con-
Handheld Instruments
trol, thermal shutdown and current limit. The LTC3440 is
MP3 Players
available in the 10-pin thermally enhanced MSOP and
Digital Cameras
(3mm × 3mm) DFN packages. , LTC and LT are registered trademarks of Linear Technology Corporation. Burst Mode is a registered trademark of Linear Technology Corporation. Protected by U.S. Patents including 6404251, 6166527.
TYPICAL APPLICATIO
Efficiency vs VINLi-Ion to 3.3V at 600m A Buck-Boost Converter
10µH VOUT = 3.3V
IOUT = 100m A
f OSC = 1MHz
SW1 SW2 VIN = 2.7V TO 4.2V LTC3440
VIN VOUT
SHDN/SS FB
MODE/SYNC VC
Li-Ion
RT GND
RT 60.4k
*1 = Burst Mode OPERATION C1: TAIYO YUDEN JMK212BJ106MG 3440 TA01
VIN (V)
0 = FIXED FREQUENCY C2: TAIYO YUDEN JMK325BJ226MM L1: SUMIDA CDRH6D38-100 3440 TA02
3440fa
Page Summary Contents For LINEAR TECHNOLOGY LTC3440 User's Manual
Manual Details
| Brand | Linear |
|---|---|
| Pages | 20 |
| File Size | 222.22 KB |
| Published | July 16, 2026 |
Enter the captcha to get the download link:
Frequently Asked Questions
Does it handle voltage differences between input and output?
Yes, the LTC3440 is a Buck-Boost converter that operates whether the input voltage is above, below, or equal to the output voltage.
What is the minimum standby current draw for battery longevity?
The shutdown quiescent current is less than 1µA, which helps maximize battery life in portable applications.
How can I customize the switching frequency?
You can program the oscillator frequency from 300kHz up to 2MHz using an external synchronizable resistor.
What is the maximum continuous output current it supports?
The device can handle up to 600mA of continuous output current, making it ideal for single lithium-ion or NiMH applications.