Linear Technology DC1123 Quick Start Manual

DC1123A QUICK START GUIDE
DESCRIPTION
Demonstration circuit 1123 is a I
nous Step-Down DC/DC Regulators featuring the
LTC3562. The LTC3562 is a quad high efficiency
monolithic synchronous step-down regulator with
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an I C interface. Two regulators are externally ad-
justable and can have their feedback voltages pro-
grammed between 425mV and 800mV in 25mV
(Type A). The other two regulators are fixed output
regulators whose output voltages can be pro-
grammed between 600mV and 3.775V in 25mV
steps (Type B). All four regulators operate inde-
pendently and can be put into pulse skip, LDO,
Burst Mode operation or forced Burst Mode opera-
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tion through I C control. The Type A regulators
have separate RUN pins that can be enabled if I
control is unavailable.
The 2.85V to 5.5V input range makes the LTC-
3562 ideally suited for single Li-ion battery pow-
ered applications. At low output load conditions,
TABLE 1. Typical Specifications (25°C)
Input Voltage Range: V
CC
P600A
P600B
P400A
P400B
OPERATING PRINCIPLES
The LTC3562 is a highly integrated power man-
agement IC that contains four I
monolithic, high efficiency step-down regulators.
Two regulators provide up to 600ma of output
current and the other two regulators produce up
Step-Down DC/DC Regulators
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C Quad Synchro- the regulators can be switched into LDO, Burst
Mode operation or forced Burst Mode operation,
extending battery life in portable systems. The qui-
escent current drops to under 100µA with all regu-
lators in LDO mode and under 0.1µA when all
regulators are shut down
Switching frequency is internally set to 2.25MHz,
allowing the use of small surface mount inductors
and capacitors. All regulators are internally com-
pensated.
The LTC3562 is offered in a low profile 3mm
3mm QFN package.
Design files for this circuit board are available.
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C
Call the LTC factory.
L
Corporation.
All other trademarks are the property of their respective owners.
2.85V to 5.5V (Subject to dropout)
0.96V to 1.82V, 600mA (Max)
1.20V to 3.775V, 600mA (Max)
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C controllable,
QUICK START GUIDE
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I C Quad Synchronous
, LTC, LTM, LT, Burst Mode, are registered trademarks of Linear Technology
0.80V to 1.51V, 400mA (Max)
0.60V to 3.775V, 400mA (Max)
to 400ma. All four regulators are 2.25MHz, con-
stant-frequency, current mode switching regula-
tors that can be independently controlled through
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I C. All regulators are internally compensated
DC1123
LTC3562
˜
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