LTC3611_15 Datasheet, PDF (1/26 Pages) Linear Technology – 10A, 32V Monolithic Synchronous Step-Down DC/DC Converter

Features
n _{10A Output Current}
n _{Wide VIN Range = 4.5V to 32V (36V Maximum)}
n _{Internal N-Channel MOSFETs}
n _{True Current Mode Control}
n _{Optimized for High Step-Down Ratios}
n _{t0N(MIN) ≤ 100ns}
n _{Extremely Fast Transient Response}
n _{Stable with Ceramic COUT}
n _{±1% 0.6V Voltage Reference}
n _{Power Good Output Voltage Monitor}
n _{Adjustable On-Time/Switching Frequency (>1MHz)}
n _{Adjustable Current Limit}
n _{Programmable Soft-Start}
n _{Output Overvoltage Protection}
n _{Optional Short-Circuit Shutdown Timer}
n _{Low Shutdown IQ: 15μA}
n _{Available in a 9mm × 9mm 64-Pin QFN Package}
Applications
n _{Point of Load Regulation}
n _{Distributed Power Systems}
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.
LTC3611
10A, 32V Monolithic
Synchronous Step-Down
DC/DC Converter
Description
The LTC^®3611 is a high efficiency, monolithic synchronous
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.
The operating frequency is selected by an external resistor
and is compensated for variations in V_IN and V_OUT.
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.
Fault protection is provided by internal foldback current
limiting, an output overvoltage comparator and an optional
short-circuit shutdown timer. Soft-start capability for sup-
ply sequencing is accomplished using an external timing
capacitor. The regulator current limit is user programmable.
A power good output voltage monitor indicates when
the output is in regulation. The LTC3611 is available in a
compact 9mm × 9mm QFN package.
Typical Application
High Efficiency Step-Down Converter
0.1µF ^VOUT
100pF
680pF
12.5k
INTV_CC
39.2k
11k
V_ON
I_ON
RUN/SS V_IN
LTC3611
SW
I_TH
BOOST
SGND INTV_CC
FCB
V_RNG
PGOOD ^PGND
EXTV_CC V_FB
3611 TA01a
182k
1µH
0.22µF
10µF
×3
V_IN
4.5V TO 32V
100µF
×2
V_OUT
2.5V
10A
4.7µF
30.1k
9.5k
Efficiency and Power Loss
vs Load Current
100
V_OUT = 2.5V
90
80
V_IN = 5V
70
V_IN = 25V
10000
1000
60
50
100
POWER LOSS,
40
V_IN = 5V
30
10
20
POWER LOSS,
10
V_IN = 25V
0
1
0.01
0.1
1
10
LOAD CURRENT (A)
3611 TA01b
3611fd