1
dc1755af
DEMO MANUAL DC1755A
DESCRIPTION
LTC3860EUH
Wide Input Range,
High Efficiency Step-Down
DC/DC Converter
Demonstration circuit DC1755A provides the user with
two high current dual phase synchronous buck converters
driven by the LTC3860. These buck converters provide
outputs of 1.5V/50A and 1.2V/50A over an input voltage
range of 6V to 14V and a switching frequency of 500kHz.
The board can be easily modified for a 4-phase, single V
O
,
100A supply. The power stage for each phase consists
of the tri-state PWM compatible 6mm × 6mm Fairchild
DrMOS module and a 0.47μH 13.2mm × 12.8mm iron
powder type inductor from Würth. A high density, two
sided drop-in layout is used. The entire converter, excluding
the bulk output and input capacitors, fits within a 2.25” ×
1.38” area on the board.
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
The main features of the board are listed below:
• High efficiency and high current density.
• Remote sensing for each output.
• Optional resistors to tie the two outputs together.
• Connector and header to tie two or more boards together
for up to 12-phase operation.
• RUN, PGOOD and TRACK/SS pins for each output.
• CLKIN and CLKOUT pins.
• Onboard bias voltage regulator.
• BNC connectors to monitor each output voltage.
Design files for this circuit board are available at
http://www.linear.com/demo
(T
A
= 25°C), no airfl ow.
PARAMETER
CONDITIONS
VALUE
Minimum Input Voltage
6V
Maximum Input Voltage
14V
Output Voltage V
OUTA
I
OUTA
= 0A to 50A, V
IN
= 6V to 14V
1.5V ± 2%
Output Voltage V
OUTB
I
OUTB
= 0A to 50A, V
IN
= 6V to 14V
1.2V ± 2%
V
OUTA
Maximum Output Current, I
OUTA
V
IN
= 6V to 14V, V
OUTA
= 1.5V
50A
V
OUTB
Maximum Output Current, I
OUTB
V
IN
= 6V to 14V, V
OUTB
= 1.2V
50A
Nominal Switching Frequency
500kHz
Efficiency
See Figures 2 and 3
V
OUTA
= 1.5V, I
OUTA
= 50A, V
IN
= 12V
90.2% Typical
V
OUTB
= 1.2V, I
OUTB
= 50A, V
IN
= 12V
89.2% Typical
