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dc2355af
DEMO MANUAL DC2355A
Description
LTC3130EUD
25V, 600mA Buck-Boost DC/DC Converter
with 1.6µA Quiescent Current
Demonstration Circuit 2355A features the
LTC
®
3130
, a
wide input voltage, wide output voltage operating range,
high efficiency, low noise monolithic DC/DC buck-boost
converter.
The LTC3130 operates from input voltages of 2.4V to 25V.
The demo board has been designed with the output voltage
set to 5V. The LTC3130 incorporates a proprietary low noise
switching algorithm which optimizes efficiency with input
voltages above, below or equal to the output voltage and
ensures seamless transitions between operating modes.
The DC2355A demo board has two user selectable operat-
ing modes: Burst Mode
®
operation and Fixed Frequency
PWM (JP2). In PWM Mode, the LTC3130 operates at
1.2MHz to allow high efficiency while minimizing the
solution footprint.
The LTC3130 features pin selectable 850mA/450mA aver-
age inductor current limit. To set the current limit to 850mA
set jumper JP1 to “HIGH”. For 450mA current limit set
JP1 to “LOW”. The lower current limit function is useful
when operating from weak, or current limited sources.
A PGOOD open drain output is provided and is pulled
up to V
OUT
. This output asserts low when V
OUT
is below
regulation.
An accurate RUN threshold can be set to enable the con-
verter at a desired input voltage. The DC2355A demo board
is set up to use R10 in conjunction with R11 to set this
L
, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode operation are registered
trademarks of Linear Technology Corporation. All other trademarks are the property of their
respective owners.
performance summary
threshold. Jumper JP4 is provided to pull this input up to
V
IN
or tie it directly to GND. See the data sheet for details.
Maximum power point control (MPPC) allows for simple
optimization of power transfer between the converter and
a non-ideal supply such as a photovoltaic panel or another
high impedance source. The DC2355A demo board can
be set to operate in MPPC mode by setting jumper JP3
to “ON”, removing R8 and populating R7 and R9. In most
applications this function can also be realized, often with
better efficiency, by using the accurate RUN comparator
functionality. See the data sheet for details.
The LTC3130 allows the internal V
CC
rail to be fed externally
from the EXTV
CC
pin. In some applications the efficiency
of the converter can be improved by allowing V
CC
to be
back-fed from a supply, such as V
OUT
. Setting the EXTV
CC
jumper (JP5) on the demo board to “EXT” back-feeds V
CC
through EXTV
CC
from V
OUT
. Setting this jumper to internal
(“INT”) powers V
CC
from the V
IN
input. See the data sheet
for additional details.
The LTC3130/LTC3130-1 data sheet has detailed informa-
tion about the operation, specifications, and applications
of the device. The data sheet should be read in conjunction
with this quick start guide.
Design files for this circuit board are available at
http://www.linear.com/demo/DC2355A
Specifications are at T
A
= 25°C
Input Voltage Range
2.4V to 25V
V
OUT
5V
I
OUT
(see Note 1)
600mA
Efficiency
See Figure 1
Note 1:
The demo board output current is a function of V
IN
. Please refer to the data sheet for more information.
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