1
dc2002af
DEMO MANUAL DC2002A
Description
LTC3774EUHE
High Efficiency Dual Output Step-Down
Converter with Very Low DCR Inductor
Demonstration circuit DC2002A is a dual output synchro-
nous buck converter featuring the
LTC3774EUHE
. The
demo board supplies two rails of 1.5V / 30A and 1.2V / 30A.
The power stage for each rail consists of a 0.33µH 0.32mΩ
DCR inductor with a 11mm
×
11mm footprint and a
6mm
×
6mm DrMOS driven by the PWM outputs of the
LTC3774EUHE at a switching frequency of 400kHz. The
inductor, DrMOS and the local ceramic input and output
capacitors forms the core converter which occupies a
1.1˝
×
1.1˝ area on the top layer. The control circuit is
directly underneath on the bottom layer and occupies an
area of 0.9˝
×
1.1˝. The result is a two sided core converter
with a current density of 50A per square inch and a full
load efficiency of 91.1% for the 1.5V rail and 90.0% for
the 1.2V rail.
L
, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and Hot Swap
is a trademark of Linear Technology Corporation. All other trademarks are the property of their
respective owners.
performance summary
Additional features of this demo board include:
•
Remote Sensing for Each Output
•
PLLIN and CLKOUT Pins
•
PGOOD, RUN and TRK/SS Pins for Each Output
•
Optional Resistors to Tie the Two Outputs Together
•
Optional Footprint for Hot Swap
™
FET on the Input of
Each Phase for MOSFET Failure Protection
•
Optional Footprint for an LTC4449 Gate Driver and
Discrete MOSFETs
•
Optional Footprint for a Dual Phase Delta Power Block
Design files for this circuit board are available at
http://www.linear.com/demo/DC2002A
PARAMETER
CONDITIONS
VALUE
Minimum Input Voltage
7V
Maximum Input Voltage
14V
Output Voltage V
OUT1
I
OUT1
= 0A TO 30A, V
IN
= 7V to 14V
1.5V ±2%
Output Voltage V
OUT2
I
OUT2
= 0A TO 30A, V
IN
= 7V to 14V
1.2V ±2%
V
OUT1
Maximum Output Current, I
OUT1
V
IN
= 7V to 14V, V
OUT1
= 1.5V
30A
V
OUT2
Maximum Output Current, I
OUT2
V
IN
= 7V to 14V, V
OUT2
= 1.2V
30A
Nominal Switching Frequency
400kHz
Efficiency
See Figures 2 and 3
V
OUT1
= 1.5V, I
OUT1
= 30A, V
IN
= 12V
91.1% Typical
V
OUT2
= 1.2V, I
OUT2
= 30A, V
IN
= 12V
90.0% Typical
Specifications are at T
A
= 25°C, No Airflow
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