LTC3108EDE
1
DESCRIPTION
Demonstration Circuit 1582B featuring the LTC3108 is
a highly integrated DC/DC converter optimized for
harvesting and managing energy from extremely low
input voltage sources such as thermoelectric genera-
tors (TEG). The step-up topology operates from input
voltages as low as 20mV.
The DC 1582B Demonstration Circuit has been optimized
for low start-up voltage with a 100:1 turns ratio trans-
former. For application where it is desirable to trade-off
a higher start-up voltage for higher current, a lower turns
ratio transformer can be used. Refer to the LTC3108
datasheet for more information.
The LTC3108 is designed to accumulate and manage
energy over a long period of time to enable short bursts
of power to be used to acquire and transmit data. The
burst must occur at a low enough duty cycle such that
the total output energy during the burst does not exceed
the average source power integrated over the accumula-
tion time between bursts.
The Demonstration Circuit has been set up with a storage
capacitor that makes it easy to evaluate the general func-
tionality of the circuit. The lower value capacitor allows
for a fast charge time but limits the pulsed energy that
can be drawn from it. Space is provided, and alternate
part footprints have been built into the PCB to allow ex-
perimentation with larger capacitors for more energy
storage. In a typical application, the larger output capaci-
tors may be used. Refer to the datasheet for more in-
formation including equations to properly size the output
capacitors for a given application.
The LTC3108 is available in two versions, the only differ-
ence being the VOUT and VOUT2 output voltages. Refer
to the datasheets for more information.
Design files for this circuit board are available. Call
the LTC factory.
L
, LTC, LTM, LT, Burst Mode, are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
DEMO CIRCUIT 1582B
QUICK START GUIDE
LTC3108EDE/ LTC3108EDE-1
Ultralow Voltage Step-Up
Converter and Power Manager
TABLE 1. Typical Specifications (25
°
C)
Input Voltage Range
50mV-400mV (Typical no load start-up = 20mV)
VLDO 2.2V
VOUT
Jumper Selectable from 2.35 to 5.0V
VOUT2
Switched Output, VOUT2=VOUT
VSTORE 5.25V
