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dc1928af
DEMO MANUAL DC1928A
DESCRIPTION
LTC3867EUF
High Efficiency Synchronous
Buck Converter
Demonstration circuit 1928A is a single output synchronous
buck converter featuring the
LTC
®
3867EUF
in a 24-lead
4mm x 4mm QFN package.
The DC1928A is configured with a sense resistor. Inductor
DCR sensing circuit is optional. Using the inductor’s DCR
as the sense element instead of the onboard sense resistor
saves cost, board space while improving efficiency. Using
a sense resistor provides 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, an
L
, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks
of Linear Technology Corporation. All other trademarks are the property of their respective
owners.
PERFORMANCE SUMMARY
optional temperature compensated DCR sense circuit,
and selectable continuous, pulse-skipping or Burst Mode
®
operation. Synchronization to an external clock is also
possible.
The input voltage range is from 18V to 36V. The LTC3867
data sheet gives a complete description of the part, opera-
tion and application information and must be read in con-
junction with this demo manual for DC1928A.
Design files for this circuit board are available at
http://www.linear.com/demo
Specifications are at T
A
= 25°C
PARAMETER
CONDITIONS / NOTES
VALUE
Input Voltage Range
18V ~ 36V
Output Voltage, V
OUT
V
IN
= 18V ~ 36V, I
OUT
= 0A ~ 12A, JP3: CCM
12V ±2% (11.76V ~ 12.24V)
Default Operating Frequency (Typical)
250kHz
External Clock Sync. Frequency Range
200kHz to 780kHz
Typical Full Load Efficiency (See Figure 3)
V
IN
= 24V, V
OUT
= 12V, I
OUT1
= 12A, f
SW
= 250kHz 97.6%
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