LT3473 Datasheet, PDF (1/12 Pages) Linear Technology – Micropower 1A Boost Converter with Schottky and Output Disconnect

FEATURES
■ _{Tiny Solution Size}
■ _{Low Quiescent Current:}
150µA in Active Mode (V_IN = 3.6V, V_OUT = 15V,
No Load)
1µA in Shutdown Mode
■ _{Internal 1A, 36V Switch}
■ _{Integrated Schottky Diode}
■ _{Integrated PNP Output Disconnect}
■ _{Internal Reference Override Pin}
■ _{PGOOD Pin}
■ _{25V at 80mA from 3.6V Input}
■ _{Auxiliary NPNs for Intermediate}
Bias Voltages (LT3473A)
■ _{Automatic Burst Mode}^® _{Operation at Light Load}
■ _{Constant Switching Frequency: 1.2MHz}
■ _{Thermal Shutdown}
■ _{Input Range: 2.2V to 16V}
■ _{Low Profile (3mm × 3mm) DFN Package (LT3473)}
■ _{Low Profile (4mmU× 3mm) DFN Package (LT3473A)}
APPLICATIO S
■ _{OLED Bias}
■ _{CCD Bias}
LT3473/LT3473A
Micropower 1A Boost
Converter with Schottky
and Output Disconnect
DESCRIPTIO
The LT^®3473/LT3473A are micropower step-up DC/DC
converters with integrated Schottky diode and output
disconnect circuitry in low profile DFN packages. The
small package size, high level of integration and the use of
tiny SMT components yield a solution size of less than
50mm². The internal 1A switch allows the device to deliver
25V at up to 80mA from a Li-Ion cell, while automatic Burst
Mode operation maintains efficiency at light load. An
auxiliary reference input (CTRL) allows the user to over-
ride the internal 1.25V feedback reference with any lower
value, allowing full control of the output voltage during
operation. A PGOOD pin sinks current when the output
voltage reaches 90% of final value.
The LT3473A includes two NPN transistors for generating
intermediate bias voltages from the output and is offered
in a 12-lead (4mm × 3mm) DFN package. The LT3473
does not include these NPNs and is offered in an 8-lead
(3mm × 3mm) package.
The rugged 36V switch and output disconnect circuitry
allow outputs up to 34V to be easily generated in a simple
boost topology.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Burst Mode is a registered trademark of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATIO
V_IN
3V TO 4.2V
4.7µF
6.8µH
PGOOD
OUT
CTRL
LT3473
SW
CAP
V_IN
SHDN
FB
GND
V_OUT
25V
2.2µF ^80mA
2M
0.47µF
100k
3473 TA01a
Conversion Efficiency and Power Loss vs Output Current
80 _{VIN = 3.6V}
500
V_OUT = 15V
75
400
70
300
65
200
60
100
55
0.1
1
10
OUTPUT CURRENT (mA)
0
100
3473 TA01b
3473f
1