1
dc2045af
DEMO MANUAL DC2045A
Description
LTC3118EUFD
18V, 2A Buck-Boost DC/DC Converter
with Low-Loss Dual Power Path
Demonstration Circuit 2045A featuring the
dual input fixed frequency synchronous buck-boost con-
verter with an intelligent integrated low-loss Power-Path™.
The unique all N-Channel architecture provides efficient
operation from either input source to a programmable
output voltage above, below or equal to the input. Volt-
age capability of up to 18V provides flexibility and voltage
margin for a variety of applications and power sources.
The LTC3118 uses a low noise, current mode architecture
with a fixed 1.2MHz PWM mode frequency that minimizes
the solution footprint. For high efficiency at light loads,
automatic Burst Mode™ operation can be selected con-
suming only 50μA of quiescent current in sleep.
Typical efficiencies for both Burst Mode and fixed frequency
are shown in Figure 1. JP2 in the FIXED FREQ position
results in low output ripple but also lower efficiency at
light loads. Moving the JP2 position to AUTOBURST
enables Burst Mode operation which improves efficiency
at light load.
L
, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks
and PowerPath is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
performance summary
System level features include selectable IDEAL DIODE
Mode (shown in Figure 2) or PRIORITY mode operation
(shown in Figure 3)
The system can be monitored through
V1GD
,
V2GD
and
PGD
(power good) indicators There are accurate RUN
comparators to program independent UVLO thresholds,
and output disconnect in shutdown. Other features include
2μA shutdown current, short-circuit protection, soft-start,
inductor current limit and thermal overload protection.
The DC2045A circuit has excellent transient load response
in both fixed frequency and automatic Burst Mode opera-
tion as shown in Figures 4 and 5.
The LTC3118 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
http://www.linear.com/demo/DC2045A
Specifications are at T
A
= 25°C
Input Voltage Range:
2.5V to 18.0V
V
OUT
5.0V
I
OUT
2.0A for V
IN
> 5.0V