1
dc2221af
DEMO MANUAL DC2221A
Description
LTC3807EFE
Low Quiescent Current,
High Voltage Step-Down Converter
Demonstration circuit 2221A is a low quiescent current,
synchronous buck converter featuring the
.
This demo board converts a 16V to 38V input voltage to
a 12V at 15A output.
The main features of this board include an internal LDO
for gate drive power from V
IN
or EXTV
CC
, RUN and
PGOOD pins, a mode selector that allows the converter
to run in constant current mode (CCM), pulse-skipping
or Burst Mode
®
operation, and selectable current limit.
The DC2221A supports an adjustable output voltage,
soft-start and tracking. The wide input voltage range of
16V to 38V is suitable for automotive and distributed DC
power systems where low quiescent current is important.
The LTC3807 data sheet gives a complete description of
this part, operation and application information. The data
sheet must be read in conjunction with this quick start
guide for demo circuit 2221A.
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.
performance summary
The 40V rated MOSFETs, which are used on DC2221A, can
be operated at their rated voltage. MOSFETs with higher
voltage rating can be used for more safety margin.
The DC2221A supports the LFPAK, PowerPAK SO-8 and
Power 56 MOSFET packages. The following logic level
(SV gate) MOSFETs can be used with DC2221A.
RJK0451DPB
Renesas
BSC093N04LS G
Infineon
Si4124DY
Vishay
FDS8447
Fairchild
For synchronization to an external clock, remove jumper
JP2 and apply sync signal on terminal SYNC.
Design files for this circuit board are available at
Specifications are at T
A
= 25°C
PARAMETER
CONDITIONS
VALUE
UNITS
Minimum Input Supply Voltage
16
V
Maximum Input Supply Voltage
38
V
Output Voltage Range
V
IN
= 16V to 38V, I
OUT
= 0A to 15A
12 ± 2%
V
Typical Switching Frequency
120
kHz
Typical Output Ripple (V
OUT
, 12V)
V
IN
= 24V; I
LOAD
= 15A
80
mV
Efficiency Typical (V
OUT
, 12V)
V
IN
= 24V; I
LOAD
= 15A
97
%
Supply Quiescent Current
V
IN
= 24V; V
OUT
= 12V, I
O
= 0A, Burst Mode
110
μA
Supply Shutdown Current
V
IN
= 24V
38
μA