LT3479_15 Datasheet, PDF (1/20 Pages) Linear Technology – 3A, Full Featured DC/DC Converter with Soft-Start and Inrush Current Protection

LT3479
3A, Full Featured DC/DC
Converter with Soft-Start
and Inrush Current Protection
FEATURES
n _{Wide Input Voltage Range: 2.5V to 24V}
n _{3A, 42V Internal Switch}
n _{High Efficiency Power Conversion: Up to 89%}
n _Soft-Start
n _{Frequency Set by External Resistor: 200kHz to}
3.5MHz
n _{Protection Against Input Short Circuits and}
Hot Plugging
n _{Low VCESAT Switch: 0.3V at 2.5A (Typical)}
n _{Capable of Positive and Negative Outputs}
n _{Available in Thermally Enhanced 14-Lead}
(4mm × 3mm) DFN and 16-Lead TSSOP Packages
APPLICATIONS
n _{High Power LED Driver}
n _{DSL Modems}
n _{Distributed Power}
DESCRIPTION
The LT^®3479 is a current mode, fixed frequency step-up
DC/DC converter with an internal 3A, 42V switch. Efficien-
cies of up to 89% can be achieved in typical applications. It
features a programmable soft-start function to limit induc-
tor current during start-up and inrush current protection
to protect the LT3479 during shorts and line transients.
Both inputs of the error amplifier are available to the user
allowing positive and negative output voltages. Through
an external resistor, the user can program the switch-
ing frequency from 200kHz to 3.5MHz. The low profile
(0.75mm) 14-pin, 4mm × 3mm DFN package provides
excellent thermal performance in a small footprint. The
LT3479 is also available in a thermally enhanced 16-pin
TSSOP package.
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.
TYPICAL APPLICATION
5V to 12V Boost Converter
V_IN
5V
2.2μF
4.7μH
V_IN V_S L
SW
FBN
SHDN
LT3479 V_REF
SS
10nF
FBP
R_T GND V_C
200k
V_OUT
12V
0.8A
10μF
23.2k
17.8k
10k
2.2nF
3479 TA01
5V to 12V Efficiency
90
85
80
75
70
65
60
0
0.2
0.4
0.6
0.8
I_OUT (A)
3479 TA02
3479fc
1