LTC3608 Datasheet, PDF (1/24 Pages) Linear Technology – 18V, 8A Monolithic Synchronous Step-Down DC/DC Converter

FEATURES
n _{8A Output Current}
n _{Wide VIN Range = 4V to 18V}
n _{Internal N-Channel MOSFETs}
n _{True Current Mode Control}
n _{Optimized for High Step-Down Ratios}
n _{tON(MIN) ≤ 100nsec}
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}
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 7mm × 8mm 52-Lead QFN Package}
APPLICATIONS
n _{Point of Load Regulation}
n _{Distributed Power Systems}
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other
trademarks are the property of their respective owners. Protected by U.S. Patents including
5481178, 6100678, 6580258, 5847554, 6304066.
LTC3608
18V, 8A Monolithic
Synchronous Step-Down
DC/DC Converter
DESCRIPTION
The LTC^®3608 is a high efficiency, monolithic synchronous
step-down DC/DC converter that can deliver up to 8A output
current from a 4V to 18V (20V maximum) input supply. It
uses a valley current control architecture to deliver very
low duty cycle operation 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 LTC3608 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 LTC3608 is available in a
compact 7mm × 8mm QFN package.
TYPICAL APPLICATION
High Efficiency Step-Down Converter
0.1μF ^VOUT
100pF
1500pF
11.3k
V_ON
I_ON
RUN/SS V_IN
LTC3608
SW
I_TH
BOOST
SGND INTV_CC
FCB
V_RNG
PGOOD ^PGND
EXTV_CC V_FB
3608 TA01a
187k
0.8μH
0.22μF
V_IN
4V TO 18V
10μF
×3
100μF
×2
V_OUT
2.5V
8A
4.7μF
30.1k
9.53k
Efficiency and Power Loss
vs Load Current
100
95
90
85
80
75
70
65
60
55
50
0.01
EFFICIENCY
10000
1000
100
POWER LOSS
10
V_IN = 12V
V_OUT = 2.5V
EXTV_CC = 5V
1
0.1
1
10
LOAD CURRENT (A)
3608 TA01b
3608fa
1