LTC3108
Ultralow Voltage Step-Up
Converter and Power Manager
FEATURES
nn Operates from Inputs of 20mV
nn Complete Energy Harvesting Power
Management System
nn Selectable VOUT of 2.35V, 3.3V, 4.1V or 5V
nn LDO: 2.2V at 3mA
nn Logic Controlled Output
nn Reserve Energy Output
nn Power Good Indicator
nn Uses Compact Step-Up Transformers
nn Small 12-Lead (3mm × 4mm) DFN or 16-Lead
SSOP Packages
APPLICATIONS
nn Remote Sensors and Radio Power
nn Surplus Heat Energy Harvesting
nn HVAC Systems
nn Industrial Wireless Sensing
nn Automatic Metering
nn Building Automation
nn Predictive Maintenance
All registered trademarks and trademarks are the property of their respective owners.
DESCRIPTION
The LTC®3108 is a highly integrated DC/DC converter
ideal for harvesting and managing surplus energy from
extremely low input voltage sources such as TEGs (ther-
moelectric generators), thermopiles and small solar cells.
The step-up topology operates from input voltages as
low as 20mV. The LTC3108 is functionally equivalent to
the LTC3108-1 except for its unique fixed VOUT options.
Using a small step-up transformer, the LTC3108 provides
a complete power management solution for wireless
sensing and data acquisition. The 2.2V LDO powers an
external microprocessor, while the main output is pro-
grammed to one of four fixed voltages to power a wire-
less transmitter or sensors. The power good indicator
signals that the main output voltage is within regulation.
A second output can be enabled by the host. A storage
capacitor provides power when the input voltage source
is unavailable. Extremely low quiescent current and high
efficiency design ensure the fastest possible charge times
of the output reservoir capacitor.
The LTC3108 is available in a small, thermally enhanced
12-lead (3mm × 4mm) DFN package and a 16-lead
SSOP package.
TYPICAL APPLICATION
Wireless Remote Sensor Application Powered From a Peltier Cell
THERMOELECTRIC
GENERATOR
++
1:100
220µF
20mV TO 500mV
1nF
330pF
C1
VSTORE
5V
+
LTC3108
C2
VOUT2
PGD PGOOD
SW
VLDO 2.2V
VS2
VOUT
3.3V
+
0.1F
6.3V
µP
2.2µF SENSORS
470µF RF LINK
VS1 VOUT2_EN
VAUX GND
3108 TA01a
1µF
Document Feedback
For more information www.analog.com
VOUT Charge Time
1000
VOUT = 3.3V
COUT = 470µF
100
10
1
1:100 Ratio
1:50 Ratio
1:20 Ratio
0
0 50 100 150 200 250 300 350 400
VIN (mV)
3108 TA01b
Rev. D
1
