LTC3601
1.5A, 15V Monolithic
Synchronous Step-Down
Regulator
DESCRIPTION
FEATURES
4V to 15V Operating Input Voltage Range
nn 1.5A Output Current
nn Up to 96% Efficiency
nn Very Low Duty Cycle Operation: 5% at 2.25MHz
nn Adjustable Switching Frequency: 800kHz to 4MHz
nn External Frequency Synchronization
nn Current Mode Operation for Excellent Line and Load
Transient Response
nn User Selectable Burst Mode® (No Load I = 300µA) or
Q
Forced Continuous Operation
nn 0.6V Reference Allows Low Output Voltages
nn Short-Circuit Protected
nn Output Voltage Tracking Capability
nn Programmable Soft-Start
nn Power Good Status Output
nn Available in Small, Thermally Enhanced 16-Pin QFN
(3mm × 3mm) and MSOP Packages
nn
APPLICATIONS
Distributed Power Systems
Lithium-Ion Battery-Powered Instruments
nn Point-of-Load Power Supply
nn
nn
L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks
and Hot Swap is a 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.
The LTC®3601 is a high efficiency, monolithic synchronous
buck regulator using a phase-lockable controlled on-time,
current mode architecture capable of supplying up to 1.5A
of output current. The operating supply voltage range is
from 4V 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 LTC3601 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 LTC3601 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
Efficiency and Power Loss vs Load Current
100
1000
90
0.1µF 2.2µH
PGOOD
TRACK
SW
VON
LTC3601
2.2µF
80
BOOST
INTVCC
FB
ITH
RT
MODE/SYNC
SGND
PGND
180k
10pF
VOUT
3.3V
1.5A
22µF
40k
3601 TA01a
EFFICIENCY (%)
22µF
VIN
RUN
70
100
60
50
40
10
30
POWER LOSS (mW)
VIN
4V TO 15V
20
VIN = 5V
VIN = 12V
10
0
0.001
0.01
0.1
1
LOAD CURRENT (A)
10
1
3601 TA01b
3601fc
For more information www.linear.com/LTC3601
1