LT3580_15 Datasheet, PDF (1/28 Pages) Linear Technology – Boost/Inverting DC/DC Converter with 2A Switch, Soft-Start, and Synchronization

LT3580
Boost/Inverting DC/DC
Converter with 2A Switch,
Soft-Start, and Synchronization
FEATURES
n _{2A Internal Power Switch}
n _{Adjustable Switching Frequency}
n _{Single Feedback Resistor Sets VOUT}
n _{Synchronizable to External Clock}
n _{High Gain SHDN Pin Accepts Slowly Varying}
Input Signals
n _{Wide Input Voltage Range: 2.5V to 32V}
n _{Low VCESAT Switch: 300mV at 1.5A (Typical)}
n _{Integrated Soft-Start Function}
n _{Easily Configurable as a Boost or Inverting Converter}
n _{User Configurable Undervoltage Lockout (UVLO)}
n _{Tiny 8-Lead 3mm × 3mm DFN and 8-Lead MSOP}
Packages
APPLICATIONS
n _{VFD Bias Supplies}
n _{TFT-LCD Bias Supplies}
n _{GPS Receivers}
n _{DSL Modems}
n _{Local Power Supply}
DESCRIPTION
The LT^®3580 is a PWM DC/DC converter containing an
internal 2A, 42V switch. The LT3580 can be configured
as either a boost, SEPIC or inverting converter. Capable
of generating 12V at 550mA or –12V at 350mA from a
5V input, the LT3580 is ideal for many local power supply
designs.
The LT3580 has an adjustable oscillator, set by a resistor
from the RT pin to ground. Additionally, the LT3580 can
be synchronized to an external clock. The free running or
synchronized switching frequency range of the part can
be set between 200kHz and 2.5MHz.
The LT3580 also features innovative SHDN pin circuitry
that allows for slowly varying input signals and an adjust-
able undervoltage lockout function.
Additional features such as frequency foldback and
soft-start are integrated. The LT3580 is available in tiny
3mm × 3mm 8-lead DFN and 8-lead MSOP packages.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. ThinSOT is a trademark of Linear Technology Corporation. All other
trademarks are the property of their respective owners.
TYPICAL APPLICATION
1.2MHz, 5V to 12V Boost Converter Achieves Over 88% Efficiency
4.2μH
V_IN
5V
V_OUT
12V
550mA
V_IN
SW
10μF
SHDN
GND
LT3580
130k
RT
FB
SYNC
2.2μF 75k
VC
SS
0.1μF
10k
1nF
3580 TA01
Efficiency and Power Loss
95
1200
90
1000
85
80
800
75
600
70
65
400
60
200
55
50
0
100 200 300 400 500
LOAD CURRENT (mA)
0
600
3580 TA01b
3580fg
1