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dc1887af
DEMO MANUAL DC1887A
Description
LTC3128
High Efficiency 2-Cell Supercapacitor
Charger and Balancer Converter
Demonstration circuit 1887 is a DC/DC supercapacitor
buck-boost charger and balancer converter featuring the
LTC
®
3128
. The DC1887A operates over 1.72V to 5.5V input
and charges the output up to 5.5V. Also, the LTC3128 has
2% precision input current limit, which allows the circuit to
operate effectively with current limited input power sources
like the USB. The 1.2MHz switching frequency operation
results in a small and efficient circuit. The converter pro-
vides high output voltage accuracy (typically ±2%) over
a 1.72V to 5.5V input. The demonstration circuit can be
easily modified to generate different output voltages.
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.
performance summary
Specifications are at T
A
= 25°C
PARAMETER
CONDITIONS
VALUE
Minimum Input Voltage
I
OUT
= 0A to 1A
1.72V
Maximum Input Voltage
I
OUT
= 0A to 1A
5.5V
V
OUT
V
IN
= 1.72V to 5.5V, I
OUT
= 0A
4.2V ±2%
Input Current Limit (Programmable to 3A)
V
IN
= 1.72V to 5.5V
0.9A
Nominal Switching Frequency
1.2MHz
The DC1887 has a small circuit footprint. It is a high per-
formance and cost effective solution for charging and
balancing supercapacitors. Please read the LTC3128 data
sheet along with this manual.
Design files for this circuit board are available at
http://www.linear.com/demo
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