LTC3418 Datasheet, PDF (1/20 Pages) Linear Technology – 8A, 4MHz, Monolithic Synchronous Step-Down Regulator

LTC3418
FEATURES
■ _{High Efficiency: Up to 95%}
■ _{8A Output Current}
■ _{2.25V to 5.5V Input Voltage Range}
■ _{Low RDS(ON) Internal Switch: 35mΩ}
■ _{Tracking Input to Provide Easy Supply Sequencing}
■ _{Programmable Frequency: 300kHz to 4MHz}
■ _{0.8V ±1% Reference Allows Low Output Voltage}
■ _{Quiescent Current: 380µA}
■ _{Selectable Forced Continuous/Burst Mode}^® _Operation
with Adjustable Burst Clamp
■ _{Synchronizable Switching Frequency}
■ _{Low Dropout Operation: 100% Duty Cycle}
■ _{Power Good Output Voltage Monitor}
■ _{Overtemperature Protected}
■ _{38-Lead Low Profile (0.75mm) Thermally Enhanced}
QFN (5mm × 7mm) Package
U
APPLICATIO S
■ _{Microprocessor, DSP and Memory Supplies}
■ _{Distributed 2.5V, 3.3V and 5V Power Systems}
■ _{Automotive Applications}
■ _{Point of Load Regulation}
■ _{Notebook Computers}
8A, 4MHz, Monolithic
Synchronous Step-Down
Regulator
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.
The LTC3418 can be configured for either Burst Mode
operation or forced continuous operation. Forced continu-
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.
, 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.
TYPICAL APPLICATIO
V_IN
2.8V TO 5.5V
2.5V/8A Step-Down Regulator
2.2M
1000pF
30.1k
4.99k
SV_IN TRACK PV_IN
R_T
SW
LTC3418
PGOOD
RUN/SS PGND
I_TH
SGND
SYNC/MODE V_FB
820pF
332Ω 4.32k
1.69k
C_IN
100µF
0.2µH
V_OUT
2.5V
C_{OUT 8A}
100µF
×2
3418 TA01a
Efficiency and Power Loss vs Load Current
100
90
80
70
60
50
40
30
20
0.01
EFFICIENCY
100000
10000
POWER LOSS
1000
100
10
V_IN = 3.3V
V_OUT = 2.5V
1
0.1
1
10
LOAD CURRENT (A)
3418 TA01b
3418f
1