LTC3412
2.5A, 4MHz, Monolithic
Synchronous Step-Down Regulator
FEATURES
■ High Efficiency: Up to 95%
■ 2.5A Output Current
■ Low Quiescent Current: 62µA
■ Low RDS(ON) Internal Switches: 85mΩ
■ Programmable Frequency: 300kHz to 4MHz
■ No Schottky Diode Required
■ ± 2% Output Voltage Accuracy
■ 0.8V Reference Allows Low Output Voltage
■ 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 Protection
■ Available in 16-Lead Thermally Enhanced TSSOP
and QFN Packages
APPLICATIONS
■ Portable Instruments
■ Battery-Powered Equipment
■ Notebook Computers
■ Distributed Power Systems
■ Cellular Telephones
■ Digital Cameras
DESCRIPTION
The LTC®3412 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 2.625V to 5.5V and provides
an adjustable regulated output voltage from 0.8V to 5V
while delivering up to 2.5A of output current. The inter-
nal synchronous power switch with 85mΩ on-resistance
increases efficiency and eliminates the need for an external
Schottky diode. Switching frequency is set by an external
resistor or can be sychronized to an external clock. 100%
duty cycle provides low dropout operation extending bat-
tery life in portable systems. OPTI-LOOP® compensation
allows the transient response to be optimized over a wide
range of loads and output capacitors.
The LTC3412 can be configured for either Burst Mode®
operation or forced continuous operation. Forced con-
tinuous operation reduces noise and RF interference
while Burst Mode operation provides high efficiency 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. To further maximize bat-
tery life, the P-channel MOSFET is turned on continuously
in dropout (100% duty cycle).
L, LT, LTC, LTM, Burst Mode, OPTI-LOOP, Linear Technology and the Linear logo are registered
trademarks and ThinSOT is a trademark of Analog Devices, Inc. All other trademarks are the
property of their respective owners.
TYPICAL APPLICATION
VIN
2.7V TO 5.5V
4.7M
470pF 15k
1000pF
309k
SVIN PVIN
RT
PGOOD
SW
LTC3412
100pF
RUN/SS
PGND
SGND
ITH
SYNC/MODE VFB
110k 392k
75k
22µF
1µH
VOUT
2.5V
100µF 2.5A
3412 F01
Figure 1. 2.5V, 2.5A Step-Down Regulator
Efficiency vs Load Current
100
80
Burst Mode OPERATION
60
FORCED CONTINUOUS
40
20
0
0.001
VIN = 3.3V
VOUT = 2.5V
0.01
0.1
1
10
LOAD CURRENT (A)
3412 G01
For more information www.linear.com/LTC3412
3412fc
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