LTC3411
1.25A, 4MHz, Synchronous
Step-Down DC/DC Converter
FEATURES
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DESCRIPTIO
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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 R
DS(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: I
Q
≤
1µA
Low Quiescent Current: 60µA
Output Voltages from 0.8V to 5V
Selectable Burst Mode
®
Operation
Sychronizable to External Clock
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.
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 interfer-
ence, the SYNC/MODE pin can be configured to skip
pulses or provide forced continuous operation.
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.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Burst Mode is a registered trademark of Linear Technology Corporation.
APPLICATIO S
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Notebook Computers
Digital Cameras
Cellular Phones
Handheld Instruments
Board Mounted Power Supplies
TYPICAL APPLICATIO
V
IN
2.63V TO 5.5V
C1
22µF
V
IN
SYNC/MODE
PGOOD
LTC3411
I
TH
13k
1000pF
324k
SHDN/R
T
SGND
PGND
412k
V
FB
PV
IN
SV
IN
SW
887k
L1
2.2µH
Efficiency vs Load Current
100
95
EFFICIENCY (%)
V
OUT
2.5V/1.25A
C2
22µF
90
85
80
75
V
IN
= 3.3V
V
OUT
= 2.5V
f
O
= 1MHz
Burst Mode OPERATION
1
100
10
LOAD CURRENT (mA)
1000
3411 TA01
NOTE: IN DROPOUT, THE OUTPUT TRACKS
THE INPUT VOLTAGE
C1, C2: TAIYO YUDEN JMK325BJ226MM
L1: TOKO A914BYW-2R2M (D52LC SERIES)
3411 F01
70
Figure 1. Step-Down 2.5V/1.25A Regulator
U
sn3411 3411fs
U
U
1
LINER [ LINEAR TECHNOLOGY ]
