LTC3525D-3.3_15 Datasheet, PDF (1/14 Pages) Linear Technology – 400mA Micropower Synchronous Step-Up DC/DC Converter with Pass Through Mode

LTC3525D-3.3
400mA Micropower
Synchronous Step-Up DC/DC
Converter with Pass Through Mode
Features
n _{VOUT Connected to VIN in Shutdown}
n _{Up to 95% Efficiency}
n _{0.85V Minimum Input Start-Up Voltage}
n _{Fixed Output Voltage of 3.3V}
n _{Delivers 60mA at 3.3V from a 1V Input,}
or 140mA at 3.3V from a 1.8V Input
n _{Burst Mode}^® _{Operation: IQ = 7µA}
n _{VIN Range: 0.5V to 4.5V}
n _{Only Three External Components}
n _{VIN > VOUT Operation}
n _{Anti-Ringing Control}
n _{Short-Circuit and Overtemperature Protection}
n _{Very Low Profile of 1mm}
n _{Tiny 6-Lead SC70 Package}
Applications
n _{MP3 Players}
n _{Portable Instruments}
n _{Glucose Meters}
n _{Digital Cameras}
L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks
and ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners. Patents pending.
Description
The LTC^®3525D-3.3 is a high efficiency synchronous step-
up DC/DC converter that can start up with an input as low
as 0.85V. It offers a compact, high efficiency alternative to
charge pumps in single cell or dual cell alkaline or Li-Ion
applications. Only three small external components are re-
quired. The LTC3525D features a fixed output voltage of 3.3V.
In shutdown, V_OUT is connected to V_IN through the inductor.
The device includes a 0.5Ω N-channel MOSFET switch and
a 0.8Ω P-channel synchronous rectifier. Peak switch current
ranges from 150mA to 400mA, depending on load, providing
enhanced efficiency. Quiescent current is an ultralow 7µA,
maximizing battery life in portable applications.
Other features include anti-ringing control and thermal
shutdown. The LTC3525D is available in a tiny 6-Lead
SC70 package.
List of LTC3525 Options
PART NAME INPUT START-UP
VOLTAGE
LTC3525-3
0.85V
LTC3525-3.3
0.85V
LTC3525-5
0.85V
LTC3525D-3.3
0.85V
LTC3525L-3
0.7V
OUTPUT
VOLTAGE
3V
3.3V
5V
3.3V
3V
V_OUT STATUS IN
SHUTDOWN MODE
Output Disconnect
Output Disconnect
Output Disconnect
Pass Through Mode
Output Disconnect
Typical Application
LTC3525D-3.3 Efficiency and
Power Loss vs Load Current
L1*
10µH
100
100
90
V_IN
1.8V TO 3.2V
PASS THROUGH ON
1µF
LTC3525D-3.3
V_IN
SW
SHDN
V_OUT
GND
GND
V_OUT
3.3V
140mA
10µF
*MURATA LQH32CN100K53
3525 TA01
80
70
60
50
40
30
20
0.01
10
EFFICIENCY
1
POWER LOSS
0.1
V_IN = 3V
V_IN = 2.4V
V_IN = 1.2V
0.01
0.1
1
10 100 1000
LOAD (mA)
LT3525 • TA02
3525d33fb
For more information www.linear.com/LTC3525D3.3
1