LTC3603
2.5A, 15V Monolithic
Synchronous Step-Down
Regulator
Description
Features
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Wide Input Voltage Range: 4.5V to 15V
2.5A Output Current
Low RDS(ON) Internal Switches: 45mΩ and 85mΩ
Programmable Frequency: 300kHz to 3MHz
Low Quiescent Current: 75µA
0.6V ±1% Reference Allows Precise,
Low Output Voltage
99% Maximum Duty Cycle
Adjustable Burst Mode® Clamp
Synchronizable to External Clock
Power Good Output Voltage Monitor
Overtemperature Protection
Overvoltage Protection
Available in 16-Lead Thermally Enhanced eMSOP
and 4mm × 4mm QFN Packages
Applications
Point-of-Load Supplies
Portable Instruments
n Communications Infrastructure
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The LTC®3603 is a high efficiency, monolithic synchronous
step-down DC/DC converter utilizing a constant-frequency,
current mode architecture. It operates from an input voltage
range of 4.5V to 15V and provides an adjustable regulated
output voltage from 0.6V to 14.5V while delivering up to
2.5A of output current. The internal synchronous power
switch with 45mΩ on-resistance increases efficiency
and eliminates the need for an external Schottky diode.
The switching frequency can either be set by an external
resistor or synchronized to an external clock. OPTI-LOOP®
compensation allows the transient response to be optimized
over a wide range of loads and output capacitors.
The LTC3603 can be configured for either Burst Mode operation or forced continuous operation. Forced continuous
operation reduces noise and RF interference, while Burst
Mode operation provides the highest efficiency at light
loads. In Burst Mode operation, external control of the burst
clamp level allows the output voltage ripple to be adjusted
according to the requirements of the application.
L, LT, LTC, LTM, Burst Mode, OPTI-LOOP Linear Technology and the Linear logo are registered
,
trademarks and ThinSOT is a trademark of Linear Technology Corporation. All other trademarks
are the property of their respective owners. Protected by U.S. Patents including 5481178,
6580258, 6498466, 6611131, 6177787, 5705919, 5847554.
Typical Application
3.3V, 2.5A, 1MHz Step-Down Regulator
Efficiency and Power Loss vs Load Current
VIN
4.5V TO 15V
1nF
0.22µF
2.2µH
PGOOD
VOUT
3.3V
100µF 2.5A
SW
TRACK/SS
SYNC/MODE VFB
105k
1000
85
100
80
75
POWER LOSS
70
PGND
ITH
EFFICIENCY
90
BOOST
LTC3603
10000
POWER LOSS (mW)
RT
4.32k
1µF
PVIN INTVCC
RUN
105k
VIN = 12V
95 VOUT = 3.3V
EFFICIENCY (%)
22µF
100
10
65
475k
60
0.001
10pF
3603 TA01
0.01
0.1
1
LOAD CURRENT (A)
1
10
3603 TA01b
3603fc
For more information www.linear.com/LTC3603
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