Datasheet
LTC3418
1
3418fb
TYPICAL APPLICATION
DESCRIPTION
8A, 4MHz, Monolithic
Synchronous Step-Down
Regulator
FEATURES
APPLICATIONS
n
High Effi ciency: Up to 95%
n
8A Output Current
n
2.25V to 5.5V Input Voltage Range
n
Low R
DS(ON)
Internal Switch: 35mΩ
n
Tracking Input to Provide Easy Supply Sequencing
n
Programmable Frequency: 300kHz to 4MHz
n
0.8V ±1% Reference Allows Low Output Voltage
n
Quiescent Current: 380μA
n
Selectable Forced Continuous/Burst Mode
®
Operation
with Adjustable Burst Clamp
n
Synchronizable Switching Frequency
n
Low Dropout Operation: 100% Duty Cycle
n
Power Good Output Voltage Monitor
n
Overtemperature Protected
n
38-Lead Low Profi le (0.75mm) Thermally Enhanced
QFN (5mm × 7mm) Package
n
Microprocessor, DSP and Memory Supplies
n
Distributed 2.5V, 3.3V and 5V Power Systems
n
Automotive Applications
n
Point of Load Regulation
n
Notebook Computers
The LTC
®
3418 is a high effi ciency, 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
u p t o 8 A o f o u t p u t c u r r e n t . T h e i n t e r n a l s y n c h r o n o u s p o w e r
switch increases effi ciency 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.
The LTC3418 can be confi gured for either Burst Mode
operation or forced continuous operation. Forced con-
tinuous operation reduces noise and RF interference
while Burst Mode operation provides high effi ciency by
reducing 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.
2.5V/8A Step-Down Regulator
Effi ciency and Power Loss vs Load Current
SV
IN
TRACK
R
T
C
IN
47μF
×4
0.2μH
LTC3418
RUN/SS
I
TH
PGOOD
SW
PGND
SGND
SYNC/MODE V
FB
332Ω
PV
IN
820pF
3418 TA01a
1000pF
C
OUT
100μF
×2
V
OUT
2.5V
8A
4.32k
1.69k
30.1k
2.2M
V
IN
2.8V TO 5.5V
4.99k
LOAD CURRENT (A)
0.01
60
EFFICIENCY (%)
POWER LOSS (mW)
80
100
0.1 1 10
3418 TA01b
40
50
70
90
30
20
1000
100000
100
10000
10
1
EFFICIENCY
POWER LOSS
V
IN
= 3.3V
V
OUT
= 2.5V
L, LT, LTC and LTM 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.