LTC3604 Datasheet, PDF (1/24 Pages) Linear Technology – 2.5A, 15V Monolithic Synchronous Step-Down Regulator

FEATURES
n _{3.6V to 15V Operating Input Voltage Range}
n _{2.5A Output Current}
n _{Up to 95% Efficiency}
n _{Very Low Duty Cycle Operation: 5% at 2.25MHz}
n _{Adjustable Switching Frequency: 800kHz to 4MHz}
n _{External Frequency Synchronization}
n _{Current Mode Operation for Excellent Line and Load}
Transient Response
n _{User Selectable Low Ripple (20mVP-P Typical)}
Burst Mode^® (No Load I_Q = 300μA) or Forced
Continuous Operation
n _{0.6V Reference Allows Low Output Voltages}
n _{Short-Circuit Protected}
n _{Output Voltage Tracking Capability}
n _{Power Good Status Output}
n _{Available in Small, Thermally Enhanced, 16-Pin QFN}
(3mm × 3mm) and MSOP Packages
APPLICATIONS
n _{Distributed Power Systems}
n _{Lithium-Ion Battery-Powered Instruments}
n _{Point-of-Load Power Supplies}
L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks
and Hot Swap is a registered trademark of Linear Technology Corporation. All other trademarks
are the property of their respective owners. Protected by U.S. Patents, including 5481178,
5847554, 6580258, 6304066, 6476589, 6774611.
LTC3604
2.5A, 15V Monolithic
Synchronous Step-Down
Regulator
DESCRIPTION
The LTC^®3604 is a high efficiency, monolithic synchronous
buck regulator using a phase-lockable controlled on-time,
current mode architecture capable of supplying up to 2.5A
of output current. The operating supply voltage range is
from 3.6V to 15V, making it suitable for a wide range of
power supply applications.
The operating frequency is programmable from 800kHz to
4MHz with an external resistor enabling the use of small
surface mount inductors. For switching noise sensitive
applications, the LTC3604 can be externally synchronized
over the same frequency range. An internal phase-locked
loop aligns the on-time of the top power MOSFET to the
internal or external clock. This unique constant frequency/
controlled on-time architecture is ideal for high step-down
ratio applications that demand high switching frequencies
and fast transient response.
The LTC3604 offers two operational modes: Burst Mode
operation and forced continuous mode to allow the user
to optimize output voltage ripple, noise, and light load
efficiency for a given application. Maximum light load
efficiency is achieved with the selection of Burst Mode
operation while forced continuous mode provides minimum
output ripple and constant frequency operation.
TYPICAL APPLICATION
High Efficiency 2.5A Step-Down Regulator
V_IN
3.6V TO 15V
22μF
2.2μF
V_IN
BOOST
RUN
PGOOD
SW
TRACK/SS
V_ON
LTC3604
INTV_CC
FB
ITH
RT
MODE/SYNC
SGND PGND
0.1μF
1μH
180k
22pF
40k
3604 TA01a
V_OUT
3.3V
2.5A
47μF
Efficiency and Power Loss vs Load Current
100
90
80
70
60
50
40
30
20
10
0
0.001
10
1
0.1
V_IN = 5V 0.01
V_IN = 12V
f_O = 2MHz
Burst Mode OPERATION
0.001
0.01
0.1
1
10
LOAD CURRENT (A)
3604 TA01b
3604f
1