LTC3600_15 Datasheet, PDF (1/28 Pages) Linear Technology – 15V, 1.5A Synchronous Rail-to-Rail Single Resistor Step-Down Regulator

LTC3600
15V, 1.5A Synchronous
Rail-to-Rail Single Resistor
Step-Down Regulator
Features
n _{Single Resistor Programmable VOUT}
n _{±1% ISET Accuracy}
n _{Tight VOUT Regulation Independent of VOUT Voltage}
n _{Easy to Parallel for Higher Current and Heat Spreading}
n _{Wide VOUT Range 0V to VIN – 0.5V}
n _{High Efficiency: Up to 96%}
n _{1.5A Output Current}
n _{Adjustable Frequency: 200kHz to 4MHz}
n _{4V to 15V VIN Range}
n _{Current Mode Operation for Excellent Line and Load}
Transient Response
n _{Zero Supply Current in Shutdown}
n _{Available in Thermally Enhanced 12-Pin}
(3mm × 3mm) DFN and MSOP Packages
Applications
n _{Voltage Tracking Supplies}
n _{Point-of-Load Power Supplies}
n _{Portable Instruments}
n _{Distributed Power Systems}
Description
The LTC3600 is a high efficiency, monolithic synchronous
buck regulator whose output is programmed with just one
external resistor. The accurate internally generated 50µA
current source on the ISET pin allows the use of a single
external resistor to program an output voltage that ranges
from 0V to 0.5V below V_IN. The V_OUT voltage feeds directly
back to the error amplifier in unity gain fashion and equals
the ISET voltage. The operating supply voltage range is 4V
to 15V, making it suitable for dual lithium-ion battery and
5V or 12V input point-of-load power supply applications.
The operating frequency is synchronizable to an external
clock or programmable from 200kHz to 4MHz with an
external resistor. High switching frequency allows the use
of small surface mount inductors. The unique constant
on-time architecture is ideal for operating at high frequency
in high step-down ratio applications that also demand fast
load transient response.
L, LT, LTC, LTM, Linear Technology, the Linear logo and OPTI-LOOP 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, 5705919,
5847554, 6580258.
Typical Application
High Efficiency, 1MHz, 1.5A Step-Down Converter
V_IN
12V
V_IN
8
LTC3600
9
BOOST
RUN
50µA
5
10µF
+
ERROR
AMP
–
PWM CONTROL
AND SWITCH
DRIVER
0.1µF
SW
7
2.2µH
ISET
1
MODE/
SYNC INTV_CC RT
6 10 3
V_OUT
11
GND PGFB
13
4
ITH PGOOD
2 12
3600 TA01a
0.1µF _49.9k
1µF
V_OUT
2.5V
22µF
Efficiency and Power Loss vs
Output Current
100
V_IN = 12V
90 _{VOUT = 2.5V}
80
DCM
70
1.0
0.9
POWER ^0.8
LOSS 0.7
60
50
40
30
20
10
0
0.001
CCM
CCM
DCM
0.01
0.1
1
LOAD CURRENT (A)
0.6
0.5
0.4
0.3
0.2
0.1
0
10
3600 TA01b
3600fc
1