LT1615 Datasheet, PDF (1/8 Pages) Linear Technology – Micropower Step-Up DC/DC Convertersin SOT-23

FEATURES
s _{Low Quiescent Current:}
20µA in Active Mode
<1µA in Shutdown Mode
s _{Operates with VIN as Low as 1V}
s _{Low VCESAT Switch: 250mV at 300mA}
s _{Tiny 5-Lead SOT-23 Package}
s _{Uses Small Surface Mount Components}
s _{High Output Voltage: Up to 34V}
U
APPLICATIO S
s _{LCD Bias}
s _{Handheld Computers}
s _{Battery Backup}
s _{Digital Cameras}
LT1615/LT1615-1
Micropower Step-Up
DC/DC Converters
in SOT-23
DESCRIPTIO
The LT^®1615/LT1615-1 are micropower step-up DC/DC
converters in a 5-lead SOT-23 package. The LT1615 is
designed for higher power systems with a 350mA current
limit and an input voltage range of 1.2V to 15V, whereas
the LT1615-1 is intended for lower power and single-cell
applications with a 100mA current limit and an extended
input voltage range of 1V to 15V. Otherwise, the two
devices are functionally equivalent. Both devices feature a
quiescent current of only 20µA at no load, which further
reduces to 0.5µA in shutdown. A current limited, fixed off-
time control scheme conserves operating current, result-
ing in high efficiency over a broad range of load current.
The 36V switch allows high voltage outputs up to 34V to
be easily generated in a simple boost topology without the
use of costly transformers. The LT1615’s low off-time of
400ns permits the use of tiny, low profile inductors and
capacitors to minimize footprint and cost in space-con-
scious portable applications.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATIO
1-Cell Li-Ion to 20V Converter for LCD Bias
V_IN
2.5V TO 4.2V
L1
10µH
D1
V_IN
SW
R1
2M
LT1615
SHDN
FB
C1
GND
R2
4.7µF
130k
C1: TAIYO YUDEN LMK316BJ475
C2: TAIYO YUDEN TMK316BJ105
D1: MOTOROLA MBR0530
L1: MURATA LQH3C100K24
20V
12mA
C2
1µF
1615/-1 TA01
Efficiency
85
80
V_IN = 4.2V
75
70
V_IN = 2.5V
V_IN = 3.3V
65
60
55
50
0.1
0.3
1
3
10 30
LOAD CURRENT (mA)
1615/-1 TA01a
1