Linear LTC3774EUHE Demo Manual

Description
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.
performance summary
PARAMETER
Minimum Input Voltage
Maximum Input Voltage
Output Voltage V
OUT1
Output Voltage V
OUT2
V Maximum Output Current, I
OUT1
V Maximum Output Current, I
OUT2
Nominal Switching Frequency
Efficiency
See Figures 2 and 3
Arrow.com.
Downloaded from
High Efficiency Dual Output Step-Down
Converter with Very Low DCR Inductor
Specifications are at T
CONDITIONS
I = 0A TO 30A, V
OUT1
I = 0A TO 30A, V
OUT2
V = 7V to 14V, V
OUT1 IN OUT1
V = 7V to 14V, V
OUT2 IN OUT2
V = 1.5V, I = 30A, V
OUT1 OUT1
V = 1.2V, I = 30A, V
OUT2 OUT2
DEMO MANUAL DC2002A
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
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.
= 25°C, No Airflow
A
= 7V to 14V
IN
= 7V to 14V
IN
= 1.5V
= 1.2V
= 12V
IN
= 12V
IN
LTC3774EUHE
VALUE
7V
14V
1.5V ±2%
1.2V ±2%
30A
30A
400kHz
91.1% Typical
90.0% Typical
dc2002af
1