LTC3122_15 Datasheet, PDF (1/26 Pages) Linear Technology – 15V, 2.5A Synchronous Step-Up DC/DC Converter with Output Disconnect

LTC3122
Features
15V, 2.5A Synchronous
Step-Up DC/DC Converter
with Output Disconnect
Description
n _{VIN Range: 1.8V to 5.5V, 500mV After Start-Up}
n _{Output Voltage Range: 2.2V to 15V}
n _{800mA Output Current for VIN = 5V and VOUT = 12V}
n _{Output Disconnects from Input When Shut Down}
n _{Synchronous Rectification: Up to 95% Efficiency}
n _{Inrush Current Limit}
n _{Up to 3MHz Adjustable Switching Frequency}
Synchronizable to External Clock
n _{Selectable Burst Mode}^® _{Operation: 25µA IQ}
n _{Output Overvoltage Protection}
n _Soft-Start
n _{<1µA IQ in Shutdown}
n _{12-Lead, 3mm × 4mm × 0.75mm Thermally}
Enhanced DFN and MSOP Packages
Applications
n _{RF Power}
n _{Piezo Actuators}
n _{Small DC Motors}
n _{12V Analog Rail From Battery, 5V, or Backup Capacitor}
L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks
and ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
The LTC^®3122 is a synchronous step-up DC/DC converter
with true output disconnect and inrush current limiting. The
2.5A current limit along with the ability to program output
voltages up to 15V makes the LTC3122 well suited for a
variety of demanding applications. Once started, opera-
tion will continue with inputs down to 500mV, extending
runtime in many applications.
The LTC3122 features output disconnect in shutdown,
dramatically reducing input power drain and enabling
V_OUT to completely discharge. Adjustable PWM switching
from 100kHz to 3MHz optimizes applications for highest
efficiency or smallest solution footprint. The oscillator
can also 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 ro-
bust protection under short-circuit, thermal overload, and
output overvoltage conditions. The LTC3122 is offered in
both a low profile 12-lead (3mm × 4mm × 0.75 mm) DFN
package and a 12-lead thermally enhanced MSOP package.
Typical Application
5V to 12V Synchronous Boost Converter with Output Disconnect
V_IN
5V
4.7µF
3.3µH
OFF ON
BURST PWM
SW
V_IN
V_OUT
LTC3122
SD
PWM/SYNC
CAP
RT
FB
57.6k
V_CC
SGND
V_C
PGND
4.7µF
100nF
210k
390pF
V_OUT
12V
800mA
1.02M
22µF
113k
10pF
3122 TA01a
Efficiency Curve
100
10
90 Burst Mode
OPERATION
80
70
PWM
1
60
50
40
30
0.1
PWM POWER LOSS
20
10
0
0.01
0.01
0.1
1
10 100 1000
LOAD CURRENT (mA)
3122 TA01b
For more information www.linear.com/LTC3122
3122fa
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