LTC3418
8A, 4MHz, Monolithic
Synchronous Step-Down
Regulator
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FEATURES
DESCRIPTIO
The LTC®3418 is a high efficiency, monolithic synchro-
nous step-down DC/DC converter utilizing a constant
frequency, current mode architecture. It operates from an
input voltage range of 2.25V to 5.5V and provides a
regulated output voltage from 0.8V to 5V while delivering
up to 8A of output current. The internal synchronous
power switch increases efficiency and eliminates the need
for an external Schottky diode. Switching frequency is set
by an external resistor or can be synchronized to an
external clock. OPTI-LOOP® compensation allows the
transient response to be optimized over a wide range of
loads and output capacitors.
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High Efficiency: Up to 95%
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8A Output Current
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2.25V to 5.5V Input Voltage Range
Low RDS(ON) Internal Switch: 35mΩ
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Tracking Input to Provide Easy Supply Sequencing
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Programmable Frequency: 300kHz to 4MHz
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0.8V ±1% Reference Allows Low Output Voltage
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Quiescent Current: 380µA
Selectable Forced Continuous/Burst Mode® Operation
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with Adjustable Burst Clamp
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Synchronizable Switching Frequency
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Low Dropout Operation: 100% Duty Cycle
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Power Good Output Voltage Monitor
Overtemperature Protected
The LTC3418 can be configured for either Burst Mode
operationorforcedcontinuousoperation.Forcedcontinu-
ous operation reduces noise and RF interference while
Burst Mode operation provides high efficiency by reduc-
ing gate charge losses at light loads. In Burst Mode
operation, external control of the burst clamp level allows
the output voltage ripple to be adjusted according to the
requirements of the application. A tracking input in the
LTC3418 allows for proper sequencing with respect to
another power supply.
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38-Lead Low Profile (0.75mm) Thermally Enhanced
QFN (5mm × 7mm) Package
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APPLICATIO S
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Microprocessor, DSP and Memory Supplies
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Distributed 2.5V, 3.3V and 5V Power Systems
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Automotive Applications
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Point of Load Regulation
, LTC and LT are registered trademarks of Linear Technology Corporation.
Burst Mode and OPTI-LOOP are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Protected by U.S. Patents, including 5481178, 6580258, 6304066, 6127815, 6498466, 6611131,
6724174.
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Notebook Computers
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TYPICAL APPLICATIO
Efficiency and Power Loss vs Load Current
2.5V/8A Step-Down Regulator
100
90
80
70
60
50
40
30
20
100000
10000
1000
100
V
IN
2.8V TO 5.5V
C
IN
100µF
EFFICIENCY
SV TRACK PV
IN
IN
0.2µH
V
2.5V
8A
OUT
R
SW
T
C
OUT
2.2M
LTC3418
30.1k
100µF
×2
PGOOD
PGND
SGND
POWER LOSS
RUN/SS
I
1000pF
TH
4.99k SYNC/MODE
V
FB
10
V
V
= 3.3V
IN
OUT
820pF
332Ω
1.69k
4.32k
= 2.5V
3418 TA01a
1
0.01
0.1
1
10
LOAD CURRENT (A)
3418 TA01b
3418f
1