1
dc1999af
DEMO MANUAL DC1999A
DESCRIPTION
LTC3111EDHD
15V, 1.5A Synchronous
Buck-Boost DC/DC Converter
Demonstration circuit 1999A is a fixed frequency syn-
chronous buck-boost converter with an extended input
and output range. The unique 4-switch, single inductor
architecture provides low noise and seamless operation
from input voltages above, below, or equal to the output
voltage.
The
features selectable PWM or Burst Mode
®
operation, and an easily synchronizable oscillator. Jumper
JP1 is provided to enable the converter. The demo board
is configured for 800kHz. A jumper, JP2, is provided to
select PWM, or Burst Mode operation. A clock signal can
also be applied to JP2 if synchronization is desired.
The LTC3111 operates with a 2.5V to 15V input voltage
range and a V
OUT
range from 2.5V to 15V. The demon-
stration board has been designed to operate with V
IN
from 2.5V to 15V and an output current up to 1.5A. For
V
IN
< 5V, I
OUT
capability is reduced. V
OUT
is set to 5.0V.
L
, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks
of Linear Technology Corporation. All other trademarks are the property of their respective
owners.
PERFORMANCE SUMMARY
Typical demo board efficiency is shown in Figure 2 for
several loads. The demo board has the provision to set an
accurate run threshold. Consult the LTC3111data sheet for
more information. The transient response of the converter
to a 100mA to 600mA transient at input voltages of 3.5V
and 12V are presented in Figures 3 and 4.
The LTC3111 data sheet has detailed information about
the operation, specifications, and applications of the part.
The data sheet should be read in conjunction with this
Quick Start Guide.
Design files for this circuit board are available at
INPUT VOLTAGE RANGE
2.5V to 15V
V
OUT
5V
I
OUT
1.5A for V
IN
> 5V
Specifications are at T
A
= 25°C
