LTC3525D-3.3 Datasheet, PDF (1/12 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
■ _{VOUT Connected to VIN in Shutdown}
■ _{Up to 95% Efficiency}
■ _{0.85V Minimum Input Start-Up Voltage}
■ _{Fixed Output Voltage of 3.3V}
■ _{Delivers 60mA at 3.3V from a 1V Input,}
or 140mA at 3.3V from a 1.8V Input
■ _{Burst Mode}^® _{Operation: IQ = 7µA}
■ _{VIN Range: 0.5V to 4.5V}
■ _{Only Three External Components}
■ _{VIN > VOUT Operation}
■ _{Antiringing Control}
■ _{Short-Circuit and Overtemperature Protection}
■ _{Very Low Profile of 1mm}
■ _{Tiny 6-Pin SC70 Package}
U
APPLICATIO S
■ _{MP3 Players}
■ _{Portable Instruments}
■ _{Glucose Meters}
■ _{Digital Cameras}
DESCRIPTIO
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
required. 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-pin SC70
package.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
Burst Mode is a registered trademark of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Patents Pending.
TYPICAL APPLICATIO
L1*
10µH
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
3525 TA01
*MURATA LQH32CN100K53
LTC3525D-3.3 Efficiency and
Power Loss vs Load Current
100
100
90
80
10
EFFICIENCY
70
60
1
POWER LOSS
50
40
30
20
0.01 0.1
1
10
LOAD (mA)
0.1
V_IN = 3V
V_IN = 2.4V
V_IN = 1.2V
0.01
100 1000
LT3525 • TA02
3525d33f
1