LTC3611
10A, 32V Monolithic
Synchronous Step-Down
DC/DC Converter
Description
FeAtures
TheLTC®3611isahighefficiency,monolithicsynchronous
step-down DC/DC converter that can deliver up to 10A
output current from a 4.5V to 32V (36V maximum) input
supply. It uses a constant on-time valley current mode
control architecture to deliver very low duty cycle opera-
tion at high frequency with excellent transient response.
Theoperatingfrequencyisselectedbyanexternalresistor
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10A Output Current
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Wide V Range = 4.5V to 32V (36V Maximum)
IN
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Internal N-Channel MOSFETs
True Current Mode Control
Optimized for High Step-Down Ratios
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t
≤ 100ns
0N(MIN)
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Extremely Fast Transient Response
Stable with Ceramic C
and is compensated for variations in V and V
.
OUT
IN
OUT
1ꢀ 0.6V Voltage Reference
The LTC3611 can be configured for discontinuous or
forced continuous operation at light load. Forced continu-
ous operation reduces noise and RF interference while
discontinuous mode provides high efficiency by reducing
switching losses at light loads.
Power Good Output Voltage Monitor
Adjustable On-Time/Switching Frequency (>1MHz)
Adjustable Current Limit
Programmable Soft-Start
Output Overvoltage Protection
Optional Short-Circuit Shutdown Timer
Low Shutdown I : 15μA
Available in a 9mm × 9mm 64-Pin QFN Package
Fault protection is provided by internal foldback current
limiting,anoutputovervoltagecomparatorandanoptional
short-circuitshutdowntimer.Soft-startcapabilityforsup-
ply sequencing is accomplished using an external timing
capacitor.Theregulatorcurrentlimitisuserprogrammable.
A power good output voltage monitor indicates when
the output is in regulation. The LTC3611 is available in a
compact 9mm × 9mm QFN package.
Q
ApplicAtions
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Point of Load Regulation
Distributed Power Systems
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L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
Patents including 5481178, 6100678, 6580258, 5847554, 6304066.
typicAl ApplicAtion
High Efficiency Step-Down Converter
Efficiency and Power Loss
vs Load Current
182k
V
OUT
V
I
0.1µF
ON
100
90
80
70
60
50
40
30
20
10
0
10000
1000
100
10
ON
V
= 2.5V
OUT
V
IN
4.5V TO 32V
RUN/SS
V
IN
10µF
×3
V
IN
= 5V
100pF
12.5k
LTC3611
V
IN
= 25V
1µH
V
2.5V
10A
OUT
SW
680pF
0.22µF
100µF
×2
I
BOOST
TH
POWER LOSS,
= 5V
V
IN
SGND INTV
CC
30.1k
9.5k
FCB
POWER LOSS,
39.2k
11k
V
= 25V
IN
4.7µF
V
INTV
CC
RNG
PGND
1
PGOOD
0.01
0.1
1
10
EXTV
CC
V
FB
LOAD CURRENT (A)
3611 TA01b
3611 TA01a
3611fd
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