LTC3105
400mA Step-Up DC/DC
Converter with Maximum Power
Point Control and 250mV Start-Up
FEATURES
DESCRIPTION
TheLTC®3105isahighefficiencystep-upDC/DCconverter
that can operate from input voltages as low as 225mV. A
250mVstart-upcapabilityandintegratedmaximumpower
pointcontroller(MPPC)enableoperationdirectlyfromlow
voltage,highimpedancealternativepowersourcessuchas
photovoltaic cells, TEGs (thermoelectric generators) and
fuelcells.AuserprogrammableMPPCsetpointmaximizes
the energy that can be extracted from any power source.
Burst Mode operation, with a proprietary self adjusting
peak current, optimizes converter efficiency and output
voltage ripple over all operating conditions.
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Low Start-Up Voltage: 250mV
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Maximum Power Point Control
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Wide V Range: 225mV to 5V
IN
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Auxiliary 6mA LDO Regulator
Burst Mode® Operation: I = 24µA
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Q
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Output Disconnect and Inrush Current Limiting
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V > V
Operation
IN
OUT
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Antiringing Control
Soft Start
Automatic Power Adjust
Power Good Indicator
10-Lead 3mm × 3mm × 0.75mm DFN and 12-Lead
MSOP Packages
The AUX powered 6mA LDO provides a regulated rail for
external microcontrollers and sensors while the main
output is charging. In shutdown, I is reduced to 10µA
and integrated thermal shutdown offers protection from
overtemperature faults. The LTC3105 is offered in 10-lead
3mm×3mm×0.75mmDFNand12-leadMSOPpackages.
L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks
and ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
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APPLICATIONS
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Solar Powered Battery/Supercapacitor Chargers
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Energy Harvesting
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Remote Industrial Sensors
Low Power Wireless Transmitters
Cell Phone, MP3, PMP and GPS Accessory Chargers
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TYPICAL APPLICATION
Single Photovoltaic Cell Li-Ion Trickle Charger
Output Current vs Input Voltage
80
10µH
MPPC DISABLED
70
225mV TO 5V
V
= 3.3V
OUT
V
SW
OUT
IN
60
50
40
30
20
10
0
+
–
V
OUT
PHOTOVOLTAIC
CELL
V
4.1V
10µF
V
= 4.2V
OUT
LTC3105
1020k
332k
V
= 5V
FB
OUT
Li-Ion
MPPC
SHDN
AUX
PGOOD
LDO
OFF
ON
2.2V
10µF
40.2k
FBLDO
GND
4.7µF
1µF
0.2 0.3
0.5 0.6 0.7 0.8 0.9 1.0
INPUT VOLTAGE (V)
0.4
3105 TA01a
3105 TA01b
3105fa
1