LTC3411AIMS(RevA) View Datasheet(PDF) - Linear Technology
Part Name
Description
Manufacturer
LTC3411AIMS Datasheet PDF : 20 Pages
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LTC3411A
1.25A, 4MHz, Synchronous
Step-Down DC/DC Converter
FEATURES
■ Uses Tiny Capacitors and Inductor
■ High Frequency Operation: Up to 4MHz
■ Low RDS(ON) Internal Switches: 0.15Ω
■ High Efficiency: Up to 96%
■ Selectable Low Ripple (25mVP-P) Burst Mode®
Operation: IQ = 40μA
■ 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
■ Output Voltages from 0.8V to 5V
■ Synchronizable to External Clock
■ Supports Pre-Biased Outputs
■ Small 10-Lead 3mm × 3mm DFN or MSOP Package
APPLICATIONS
■ Notebook Computers
■ Digital Cameras
■ Cellular Phones
■ Handheld Instruments
■ Board Mounted Power Supplies
DESCRIPTION
The LTC®3411A is a constant frequency, synchronous
step-down DC/DC converter. Intended for medium power
applications, it operates from a 2.5V 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 1mm or less in height. The output voltage is
adjustable from 0.8V to 5.5V. Internal synchronous power
switches provide high efficiency. The LTC3411A’s current
mode architecture and external compensation allow the
transient response to be optimized over a wide range of
loads and output capacitors.
The LTC3411A can be configured for automatic power
saving Burst Mode operation (IQ = 40μA) 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.
To further maximize battery life, the P-channel MOSFET
is turned on continuously in dropout (100% duty cycle).
In shutdown, the device draws <1μA.
L, LT, LTC, LTM and Burst Mode 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, 6498466, 6611131.
TYPICAL APPLICATION
Step-Down 2.5V/1.25A Regulator
VIN
2.5V TO 5.5V
SYNC
SYNC/MODE
PVIN
PGOOD
SVIN
SW
LTC3411A
10μF
2.2μH
22pF
VOUT
2.5V
1.25A
12.1k
680pF
ITH
SHDN/RT
SGND
549k
VFB
PGND
887k
412k
3411a TA01a
22μF
Efficiency and Power Loss vs Output Current
100
1
90
80
0.1
70
60
50
0.01
40
30
0.001
20
VIN = 2.7V
VIN = 3.6V
10
VIN = 4.2V
0
0.0001
0.1
1
10 100 1000 10000
OUTPUT CURRENT (mA)
fO = 1MHz
Burst Mode OPERATION
3411A TA01b
3411afa
1
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