Linear Technology DC1822A Demo Manual

Description
Demonstration circuit 1822A is a dual output synchronous
buck converter featuring the LTC
provides two outputs of 1.5V/25A and 1.2V/25A from
an input voltage of 7V to 14V at a switching frequency
of 500kHz. The power stage consists of a 6mm × 6mm
DrMOS and a 13mm × 13mm iron powder type inductor.
An on-board 5V LT 3470 buck regulator provides the 5V
®
bias for the LTC3861 and the DrMOS.
The demo board uses a high density, two sided drop-in
layout. The power components, excluding the bulk output
and input capacitors, fit within a 1.5" × 1.2" area on the
top layer. The control circuit fits in a 1.1" × 1.0" area on
the bottom layer. The package style for the LTC3861EUHE
is a 36-lead 5mm × 6mm QFN.
L, LT, LTC, LTM, µModule, 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
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)
3861EUHE. The board
®
(T = 25°C), no airflow
A
CONDITION
I = 0A to 25A, V
OUT1
I = 0A to 25A, V
OUT2
V = 7V to 14V, V
OUT1 IN
V = 7V to 14V, V
OUT2 IN
V = 1.5V, I
OUT1
V = 1.2V, I
OUT2
DEMO MANUAL DC1822A
High Current, Dual Output
Synchronous Buck Converter
The main features of the board are:
• Remote sensing for each output, where the divider
is placed before a high input impedance differential
amplifier.
• CLKIN and CLKOUT pins.
• Optional resistors to tie the two outputs together.
• Connector and header to tie two or more boards together
for up to 12-phase operation.
• 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
= 7V to 14V
IN
= 7V to 14V
IN
= 1.5V
OUT1
= 1.2V
OUT2
= 25A, V = 12V
OUT1 IN
= 25A, V = 12V
OUT2 IN
LTC3861EUHE
VALUE
7V
14V
1.5V ±2%
1.2V ±2%
25A
25A
500kHz
91.6% Typical
90.7% Typical
dc1822af
1