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dc2359afb
DEMO MANUAL DC2359A
Description
LTC3624
High Efficiency Synchronous
Step-Down Regulator with
Ultralow Quiescent Current
Demonstration circuit 2359A is a synchronous step-down
regulator using
LTC
®
3624HMSE
monolithic buck regulator.
The DC2359A operates from an input voltage range of 2.7V
to 17V and provides and adjustable output voltage range
from 1.2V to 5V (V
OUT
< V
IN
) at 2A of continuous output
current. A user-selectable mode input is provided with
the following options: Burst Mode
®
operation provides
the highest efficiency at light loads, while Pulse-Skipping
mode (PS) provides the lowest output voltage ripples.
Forced Continuous mode (FC) is also available for low
EMI and noise interference.
The MODE/SYNC pin can also be used to synchronize
the switching frequency to an external clock signal. The
switching frequency is fixed at 1MHz with a ±40% sync
capture range.
The regulator features ultralow quiescent current and high
efficiencies over a wide V
IN
and V
OUT
range. DC2359A
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
uses very low profile surface mount components and all
ceramic output capacitor solutions. The compact 12-lead
MSE (5mm × 4mm × 1mm) thermally enhanced package
makes LTC3624HMSE an excellent choice for battery
powered equipment, emergency radio and general pur-
pose step-down power supplies. The H-Grade version is
specified over an operating junction temperature range
of –40°C to 150°C, typically required for automotive, in-
dustrial and military applications that are subject to high
ambient temperatures.
It is recommended to read the data sheet and demo manual
of LTC3624 prior using or making any changes to DC2359A.
Design files for this circuit board are available at
http://www.linear.com/demo/DC2359A
Specifications are at T
A
= 25°C
PARAMETER
CONDITIONS
VALUE
Input Voltage Range
2.7V to 17V
On Board User Selectable Output Voltages
V
IN
= 2.7V to 17V, I
OUT
= 2A
(V
OUT
< V
IN
)
1.2V, 1.8V, 2.5V, 3.3V and 5V
Default Mode Setting
JP2
Burst Mode (“BM” on Circuit Board)
Fixed Switching Frequency
Internally Programmed Frequency
1MHz ±20%
Default Output Voltage V
OUT
V
IN
= 12V, V
OUT
= 5V, I
OUT
= 0A to 2A
5V ±2%
Maximum Continuous Output Current I
OUT
2A
Output Voltage Ripples (Peak to Peak)
V
IN
= 12V, V
OUT
= 5V, I
OUT
= 2A
8.8mV (Figure 7)
Load Transient Response
V
IN
= 12V, V
OUT
= 5V, I
OUT_STEP
= 1A to 2A,
C
OUT
= 1 × 47µF
219mV (Figure 8)
Thermal Performance
V
IN
= 12V, V
OUT
= 5V, I
OUT
= 2A,
f
SW
= 1MHz, T
A
= 25°C
Figure 9
Efficiency
V
IN
= 12V, V
OUT
= 5V, I
OUT
= 2A, BM,
f
SW
= 1MHz, T
A
= 25°C
89.7% (Figure 3)
