Linear Technology DC2355A Manual

Description
Demonstration Circuit 2355A features the
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
®
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 . This output asserts low when V
OUT
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
performance summary
Input Voltage Range
I
OUT
Note 1: The demo board output current is a function of V
25V, 600mA Buck-Boost DC/DC Converter
LTC 3130, a
®
operation and Fixed Frequency
is below
OUT
Specifications are at T
V
OUT
(see Note 1)
Efficiency
. Please refer to the data sheet for more information.
IN
DEMO MANUAL DC2355A
with 1.6µA Quiescent Current
threshold. Jumper JP4 is provided to pull this input up to
V or tie it directly to GND. See the data sheet for details.
IN
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
from the EXTV pin. In some applications the efficiency
CC
of the converter can be improved by allowing V
back-fed from a supply, such as V
jumper (JP5) on the demo board to "EXT" back-feeds V
through EXTV from V
CC
("INT") powers V
CC
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
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.
= 25°C
A
LTC3130EUD
rail to be fed externally
CC
. Setting the EXTV
OUT
. Setting this jumper to internal
OUT
from the V input. See the data sheet
IN
2.4V to 25V
5V
600mA
See Figure 1
to be
CC
CC
CC
dc2355af
1