Linear Technology DC1771A Demo Manual

DESCRIPTION
Demonstration circuit 1771A is a single output synchro-
nous buck converter featuring the LTC
24-lead 4mm × 4mm QFN package.
The DC1771A is configured with a sense resistor. DCR
sensing circuit is optional. Using the inductor's DCR as
the sense element instead of the on-board sense resistor
saves cost and board space while improving full-load
efficiency over 2%, though the sense resistor provides a
more accurate current limit.
The board has a lot of features including an internal 5V
linear regulator for bias, output voltage remote sense,
programmable nonlinear control to improve load tran-
sient performance, programmable thermal shutdown,
PERFORMANCE SUMMARY
PARAMETER
Input Voltage Range
Output Voltage V
OUT
Default Operating Frequency
External Clock Sync. Frequency Range
Typical Full-Load Efficiency (See Figure 4)
Synchronous Buck Converter
optional temperature compensated DCR sense circuit, a
® 3867EUF with a mode selector that allows the converter to run in CCM,
pulse-skipping or Burst Mode
to an external clock is also possible.
The input voltage range is from 4.5V to 14V. The LTC3867
data sheet gives a complete description of the part, op-
eration and application information and must be read in
conjunction with this demo manual for DC1771A.
Design files for this circuit board are available at
http://www.linear.com/demo
L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks
of Linear Technology Corporation. All other trademarks are the property of their respective
owners.
(T = 25°C)
A
CONDITIONS/NOTES
V = 4.5V ~ 14V, I = 0A ~ 15A, JP3: CCM
IN OUT
V = 12V, V = 1.5V, I = 15A, f
IN OUT OUT1
DEMO MANUAL DC1771A
with Remote Sensing
VALUE
4.5V ~ 14V
1.5V ±2% (1.470V ~ 1.530V)
400kHz
400kHz to 780kHz
= 400kHz 88.3%
SW
LTC3867EUF
® operation. Synchronization
dc1771af
1