LTC3124_15 Datasheet, PDF (1/28 Pages) Linear Technology – 15V, 5A 2-Phase Synchronous Step-Up DC/DC Converter with Output Disconnect

LTC3124
15V, 5A 2-Phase Synchronous
Step-Up DC/DC Converter with
Output Disconnect
FEATURES
n _{VIN Range: 1.8V to 5.5V, 500mV After Start-Up}
n _{Adjustable Output Voltage: 2.5V to 15V}
n _{1.5A Output Current for VIN = 5V and VOUT = 12V}
n _{Dual-Phase Control Reduces Output Voltage Ripple}
n _{Output Disconnects from Input When Shut Down}
n _{Synchronous Rectification: Up to 95% Efficiency}
n _{Inrush Current Limit}
n _{Up to 3MHz Programmable Switching Frequency}
Synchronizable to External Clock
n _{Selectable Burst Mode}^® _{Operation: 25µA IQ}
n _{Output Overvoltage Protection}
n _{Internal Soft-Start}
n _{<1µA IQ in Shutdown}
n _{16-Lead, Thermally- Enhanced 3mm × 5mm ×}
0.75mm DFN and TSSOP Packages
APPLICATIONS
n _{RF, Microwave Power Amplifiers}
n _{Piezo Actuators}
n _{Small DC Motors, Thermal Printers}
n _{12V Analog Rail from Battery, 5V, or Backup Capacitor}
L, LT, LTC, LTM, Burst Mode, 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.
DESCRIPTION
The LTC^®3124 is a dual-phase, synchronous step-up DC/
DC converter with true output disconnect and inrush
current limiting capable of providing output voltages up
to 15V. Dual-phase operation significantly reduces peak
inductor and capacitor ripple currents, minimizing induc-
tor and capacitor size. The 2.5A per phase current limit,
along with the ability to program output voltages up to 15V
make the LTC3124 well suited for a variety of demanding
applications. Once started, operation will continue with
inputs down to 500mV.
The LTC3124 switching frequency can be programmed
from 100kHz to 3MHz to optimize applications for highest
efficiency or smallest solution footprint. The oscillator can
be synchronized to an external clock for noise sensitive
applications. Selectable Burst Mode operation reduces
quiescent current to 25µA, ensuring high efficiency across
the entire load range. An internal soft-start limits inrush
current during start-up.
Other features include a <1µA shutdown current and robust
protection under short-circuit, thermal overload, and output
overvoltage conditions. The LTC3124 is offered in both
16-lead DFN and thermally-enhanced TSSOP packages.
TYPICAL APPLICATION
5V to 12V Synchronous Boost Converter
4.7µH
V_IN
5V
SWB
CAP
100nF
V_OUT
4.7µH
PGNDB V_OUTB
22µF
12V
1.5A
SWA
V_OUTA
×2
LTC3124
PGNDA
V_IN
SGND
BURST PWM PWM/SYNC SD
10µF
V_CC
FB
RT
V_C
4.7µF
28k
OFF ON
84.5k
680pF
1.02M
113k
56pF
3124 TA01a
Efficiency Curve
100
10
90 ^{Burst Mode}
OPERATION
80
1
70
PWM
60
0.1
50
40
30
20
10
0
0.01
Burst Mode
OPERATION
0.01
PWM
f_SW = 1MHz ^0.001
EFFICIENCY
POWER LOSS
0.0001
0.1
1
10 100 1000
LOAD CURRENT (mA)
3124 TA01b
For more information www.linear.com/LTC3124
3124f
1