Linear Technology DC2221A Demo Manual

Description
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
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.
performance summary
PARAMETER
Minimum Input Supply Voltage
Maximum Input Supply Voltage
Output Voltage Range
Typical Switching Frequency
Typical Output Ripple (V , 12V)
OUT
Efficiency Typical (V , 12V)
OUT
Supply Quiescent Current
Supply Shutdown Current
High Voltage Step-Down Converter
LTC 3807EFE.
®
or EXTV , RUN and
IN CC
Specifications are at T
CONDITIONS
V = 16V to 38V, I
IN
V = 24V; I
IN LOAD
V = 24V; I
IN LOAD
V = 24V; V
IN OUT
V = 24V
IN
DEMO MANUAL DC2221A
Low Quiescent Current,
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
BSC093N04LS G
Si4124DY
FDS8447
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
http://www.linear.com
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.
= 25°C
A
= 0A to 15A
OUT
= 15A
= 15A
= 12V, I = 0A, Burst Mode
O
LTC3807EFE
Renesas
Infineon
Vishay
Fairchild
VALUE UNITS
16
38
12 ± 2%
120 kHz
80
97
110
38
dc2221af
1
V
V
V
mV
%
μA
μA