LTC3412A Datasheet, PDF (1/20 Pages) Linear Technology – 3A, 4MHz, Monolithic Synchronous Step-Down Regulator

LTC3412A
3A, 4MHz, Monolithic
Synchronous Step-Down Regulator
FEATURES
■ _{High Efficiency: Up to 95%}
■ _{3A Output Current}
■ _{Low Quiescent Current: 64μA}
■ _{Low RDS(ON) Internal Switch: 77mΩ}
■ _{2.25V to 5.5V Input Voltage Range}
■ _{Programmable Frequency: 300KHz to 4MHz}
■ _{±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 Protected}
■ _{Available in 16-Lead Exposed Pad TSSOP and}
QFN Packages
U
APPLICATIO S
■ _{Point-of-Load Regulation}
■ _{Notebook Computers}
■ _{Portable Instruments}
■ _{Distributed Power Systems}
DESCRIPTIO
The LTC^®3412A 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 2.25V to 5.5V and provides a
regulated output voltage from 0.8V to 5V while deliver-
ing up to 3A of output current. The internal synchronous
power switch with 77mΩ on-resistance increases efficiency
and eliminates the need for an external Schottky diode.
Switching frequency is set by an external resistor or can
be synchronized 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 optimized over a wide range of
loads and output capacitors.
The LTC3412A can be configured for either Burst Mode
operation or forced continuous operation. Forced continu-
ous 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 application
requirements.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
Burst Mode and OPTI-LOOP 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, 6304066, 6127815, 6498466,
6611131, 6724174.
TYPICAL APPLICATIO
22μF
V_IN
3.3V
2.2M
294k
PV_IN SV_IN
RT
PGOOD
LTC3412A
SW
1000pF
820pF
12.1k
RUN/SS PGND
I_TH
SGND
SYNC/MODE V_FB
69.8k
115k
0.47μH
392k
V_OUT
2.5V AT 3A
C_OUT
100μF
×2
3412A F01a
Figure 1. 2.5V/3A Step-Down Regulator
Efficiency and Power Loss
100
95
90
85
80
75
70
65
60
55
50
0.01
EFFICIENCY
POWER LOSS
0.1
1
LOAD CURRENT (A)
100000
10000
1000
100
10
1
10
3412A F01b
3412afc
1