LTC3108
Ultralow Voltage Step-Up
Converter and Power Manager
FEATURES
n
n
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 (thermoelectric
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 V
OUT
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 programmed to
one of four fixed voltages to power a wireless 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.
n
n
n
Operates from Inputs of 20mV
Complete Energy Harvesting Power
Management System
- Selectable V
OUT
of 2.35V, 3.3V, 4.1V or 5V
- LDO: 2.2V at 3mA
- Logic Controlled Output
- Reserve Energy Output
Power Good Indicator
Uses Compact Step-Up Transformers
Small 12-Lead (3mm
×
4mm) DFN or 16-Lead
SSOP Packages
APPLICATIONS
n
n
n
n
n
n
n
Remote Sensors and Radio Power
Surplus Heat Energy Harvesting
HVAC Systems
Industrial Wireless Sensing
Automatic Metering
Building Automation
Predictive Maintenance
L,
LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
Wireless Remote Sensor Application Powered From a Peltier Cell
1nF
1:100
+
THERMOELECTRIC
GENERATOR
20mV TO 500mV
V
OUT
Charge Time
C1
VSTORE
LTC3108
C2
SW
V
OUT2
PGOOD
PGD
2.2V
VLDO
5V
+
220μF
330pF
+
1000
0.1F
6.3V
100
μP
TIME (sec)
2.2μF SENSORS
10
V
OUT
= 3.3V
C
OUT
= 470μF
VS2
V
OUT
3.3V
+
470μF
RF LINK
1
1:100 Ratio
1:50 Ratio
1:20 Ratio
0
50
100 150 200 250 300 350 400
V
IN
(mV)
3108 TA01b
VS1 V
OUT2_EN
VAUX
GND
1μF
3108 TA01a
0
3108fb
1
LINEAR [ LINEAR INTEGRATED SYSTEMS ]
