LTC3605_15 Datasheet, PDF (1/22 Pages) Linear Technology – 15V, 5A Synchronous Step-Down Regulator

Features
nn _{High Efficiency: Up to 96%}
nn _{5A Output Current}
nn _{4V to 15V VIN Range}
nn _{Integrated Power N-Channel MOSFETs}
(70mΩ Top and 35mΩ Bottom)
nn _{Adjustable Frequency 800kHz to 4MHz}
nn _PolyPhase^® _{Operation (Up to 12 Phases)}
nn _{Output Tracking}
nn _{0.6V ±1% Reference Accuracy}
nn _{Current Mode Operation for Excellent Line and Load}
Transient Response
nn _{Shutdown Mode Draws Less Than 15µA Supply Cur-}
rent
nn _{Available in 24-Pin (4mm × 4mm) QFN Package}
Applications
nn _{Point of Load Power Supply}
nn _{Portable Instruments}
nn _{Distributed Power Systems}
nn _{Battery-Powered Equipment}
LTC3605
15V, 5A Synchronous
Step-Down Regulator
Description
The LTC^®3605 is a high efficiency, monolithic synchronous
buck regulator using a phase lockable controlled on-time
constant frequency, current mode architecture. PolyPhase
operation allows multiple LTC3605 regulators to run out of
phase while using minimal input and output capacitance.
The operating supply voltage range is from 15V down to
4V, making it suitable for dual lithium-ion battery inputs
as well as point of load power supply applications from
a 12V or 5V rail.
The operating frequency is programmable from 800kHz to
4MHz with an external resistor. The high frequency capa-
bility allows the use of small surface mount inductors. For
switching noise sensitive applications, it can be externally
synchronized from 800kHz to 4MHz. The PHMODE pin
allows user control of the phase of the outgoing clock
signal. The unique constant frequency/controlled on-time
architecture is ideal for high step-down ratio applications
that are operating at high frequency while demanding
fast transient response. Two internal phase-lock loops
synchronize the internal oscillator to the external clock
and also servos the regulator on-time to lock on to either
the internal clock or the external clock if it’s present.
L, LT, LTC, LTM, Linear Technology, Linear logo, PolyPhase 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,
5847554, 6580258, 6304066, 6476589, 6774611.
Typical Application
V_IN
4V TO 15V
High Efficiency 1MHz, 5A Step-Down Regulator
22µF
×2
V_IN
PV_IN
SV_IN
CLKOUT INTV_CC
CLKIN
PGOOD ^BOOST
LTC3605
SW
V_ON
RUN
FB
ITH
RT
162k
2.2µF
0.1µF _1µH
11.5k
16k
220pF
3605 TA01a
2.55k
V_OUT
3.3V
47µF
×2
PGND
Efficiency and Power Loss
100
10
V_IN = 12V
V_OUT = 3.3V
90 f = 1MHz
80
70
V_OUT = 1.2V
1
60
50
40
30
V_OUT = 3.3V _{VOUT = 1.2V}
0
20
10
0
0.1
10
100
1000
10000
OUTPUT CURRENT (mA)
3605 TA01b
For more information www.linear.com/LTC3605
3605fd
1