LTC3411
1.25A, 4MHz, Synchronous
Step-Down DC/DC Converter
FEATURES
DESCRIPTION
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The LTC®3411 is a constant frequency, synchronous,
step- down DC/DC converter. Intended for medium power
applications, it operates from a 2.63V to 5.5V input voltage
range and has a user configurable operating frequency
up to 4MHz, allowing the use of tiny, low cost capacitors
and inductors 2mm or less in height. The output voltage
is adjustable from 0.8V to 5V. Internal sychronous 0.11Ω
power switches with 1.6A peak current ratings provide
high efficiency. The LTC3411’s current mode architecture
and external compensation allow the transient response
to be optimized over a wide range of loads and output
capacitors.
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Small 10-Lead MSOP or DFN Package
Uses Tiny Capacitors and Inductor
High Frequency Operation: Up to 4MHz
High Switch Current: 1.6A
Low RDS(ON) Internal Switches: 0.110Ω
High Efficiency: Up to 95%
Stable with Ceramic Capacitors
Current Mode Operation for Excellent Line
and Load Transient Response
Short-Circuit Protected
Low Dropout Operation: 100% Duty Cycle
Low Shutdown Current: IQ ≤ 1μA
Low Quiescent Current: 60μA
Output Voltages from 0.8V to 5V
Selectable Burst Mode® Operation
Synchronizable to External Clock
The LTC3411 can be configured for automatic power saving Burst Mode operation to reduce gate charge losses
when the load current drops below the level required for
continuous operation. For reduced noise and RF interference, the SYNC/MODE pin can be configured to skip pulses
or provide forced continuous operation.
APPLICATIONS
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Notebook Computers
Digital Cameras
Cellular Phones
Handheld Instruments
Board Mounted Power Supplies
To further maximize battery life, the P-channel MOSFET
is turned on continuously in dropout (100% duty cycle)
with a low quiescent current of 60μA. In shutdown, the
device draws <1μA.
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
Burst Mode is a registered trademark of Linear Technology Corporation.
TYPICAL APPLICATION
VIN
2.63V TO 5.5V
Efficiency vs Load Current
100
C1
22μF
SYNC/MODE
PVIN
PGOOD
SVIN
LTC3411
SW
ITH
1000pF
887k
VFB
SHDN/RT
13k
95
L1
2.2μH
SGND
PGND
324k
VOUT
2.5V/1.25A
C2
22μF
EFFICIENCY (%)
VIN
90
85
80
412k
VIN = 3.3V
VOUT = 2.5V
fO = 1MHz
Burst Mode OPERATION
75
NOTE: IN DROPOUT, THE OUTPUT TRACKS
THE INPUT VOLTAGE
C1, C2: TAIYO YUDEN JMK325BJ226MM
L1: TOKO A914BYW-2R2M (D52LC SERIES)
3411 F01
Figure 1. Step-Down 2.5V/1.25A Regulator
70
1
10
100
LOAD CURRENT (mA)
1000
3411 TA01
3411fb
1
