Linear Technology DC2005A, Руководство пользователя

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dc2005af
DEMO MANUAL DC2005A
DESCRIPTION
LTC3624EDD
High Efficiency Synchronous Step-Down
Regulator with Ultralow Quiescent Current
Demonstration circuit DC2005A is a synchronous step-
down regulator using an LTC
®
3624 monolithic buck
regulator. The DC2005A operates from an input voltage
range of 2.7V to 17V and provides an adjustable output
voltage range from 1.2V to 5V (V
OUT
< V
IN
) at 2A of output
current. A user-selectable mode input is provided to allow
the user to trade off ripple noise for light load efficiency.
Burst Mode
®
operation provides the highest efficiency at
light load, while pulse-skipping mode provides the lowest
voltage ripple. The MODE pin can also be used to sync the
switching frequency to an external clock.
The switching frequency is fixed at 1MHz or 2.25MHz
with a ±40% synchronizing range. The regulator features
ultralow quiescent current and high efficiency over a wide
V
OUT
range.
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.
The DC2005A uses very low profile surface mount com-
ponents and all ceramic output capacitors. The compact
8-lead DFN (3mm × 3mm) package makes the LTC3624 an
excellent choice for battery-powered equipment, general
purpose step-down power supply, and emergency radio
applications.
It is recommended to read the data sheet and demo manual
of the LTC3624 prior using or making any changes to
DC2005A.
Design files for this circuit board are available at
http://www.linear.com/demo
PERFORMANCE SUMMARY
Specifications are at T
A
= 25°C
PARAMETER CONDITIONS VALUE
Input Voltage Range 2.7V to 17V
Onboard 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 Operation (BM)
Default Switching Frequency 1MHz
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 9.4mV (See Figure 5)
Load Transient Response V
IN
= 12V, V
OUT
= 5V, I
OUT
= 1A to 2A See Figure 6
Thermal Image V
IN
= 12V, V
OUT
= 5V, I
OUT
= 2A, 1MHz See Figure 7
Efficiency V
IN
= 12V, V
OUT
= 5V, I
OUT
= 2A, BM, 1MHz 90.4% (See Figure 3 )