LTC3412
2.5A, 4MHz, Monolithic
Synchronous Step-Down Regulator
FEATURES
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DESCRIPTIO
High Efficiency: Up to 95%
2.5A Output Current
Low Quiescent Current: 62μA
Low R
DS(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
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 internal
synchronous power switch with 85mΩ on-resistance
increases efficiency and eliminates the need for an exter-
nal 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 battery life in portable systems. OPTI-LOOP
®
compensation allows the transient response to be opti-
mized 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 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. To further maximize
battery life, the P-channel MOSFET is turned on continu-
ously in dropout (100% duty cycle).
, LT, LTC, LTM, Burst Mode and OPTI-LOOP are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
APPLICATIO S
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Portable Instruments
Battery-Powered Equipment
Notebook Computers
Distributed Power Systems
Cellular Telephones
Digital Cameras
TYPICAL APPLICATIO
V
IN
2.7V TO 5.5V
SV
IN
R
T
4.7M
309k
Efficiency vs Load Current
22μF
PV
IN
PGOOD
SW
LTC3412
RUN/SS
470pF
15k
1000pF
100pF
PGND
SGND
I
TH
SYNC/MODE V
FB
110k
75k
392k
3412 F01
100
V
OUT
2.5V
2.5A
EFFICIENCY (%)
1μH
100μF
80
Burst Mode OPERATION
60
FORCED CONTINUOUS
40
20
V
IN
= 3.3V
V
OUT
= 2.5V
0.01
0.1
1
LOAD CURRENT (A)
10
3412 G01
0
0.001
Figure 1. 2.5V, 2.5A Step-Down Regulator
U
3412fb
U
U
1
LINER [ LINEAR TECHNOLOGY ]
