1
dc1853af
DEMO MANUAL DC1853A
The demo circuit has small circuit footprint, and can be
modified to generate different output voltages. The perfor-
mance can be optimized for different input voltage ranges
as well. It is a high performance and cost-effective solution
for battery-operated systems, telecom, and automotive
applications.
The LT3959 data sheet gives a complete description of
the part, operation and application information. The data
sheet must be read in conjunction with this quick start
guide. Proper board layout is essential for both proper
operation and maximum thermal performance. See the
Applications Information section of the data sheet for
more information.
Design files for this circuit board are available at
http://www.linear.com/demo
DESCRIPTION
LT3959
Wide Input Voltage Range
Boost/SEPIC/Inverting Converter
The LT
®
3959 is a current mode DC/DC converter with an
integrated 6A, 40V switch. It can operate over an input
range of 1.6V to 40V, suitable for applications from single-
cell lithium-ion battery portable electronics up to high
voltage automotive and industrial power supplies. It also
exhibits low shutdown quiescent current of <1A, making
it an ideal fit for battery-operated systems. Thanks to a
novel FBX pin architecture, the LT3959 can be connected
directly to a divider from either positive or negative output
to ground. It also packs many popular features such as
soft-start, input undervoltage lockout, adjustable frequency
and synchronization.
Demonstration circuit 1853A features LT3959 in a 300kHz
boost converter, designed for 12V output from 2V to 10V
input (V
IN
). The performance is summarized in the table
below.
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 MIN TYP MAX UNITS
Input Voltage Range 210V
Input Turn-On Voltage (Rising) 2.5 V
Input Undervoltage Lockout (Falling) 2V
Switching Frequency I
OUT
= 0.5A 300 kHz
Output Voltage 11.64 12 12.36 V
Maximum Output Current V
IN
≥ 2V 0.5 A
V
IN
≥ 5V 1 A
V
IN
≥ 9V 2 A
Output Voltage Ripple V
IN
= 5V, I
OUT
= 1A 75 100 mV
Efficiency V
IN
= 10V, I
OUT
= 2A 94 %
